Prasanna

You can Download Samacheer Kalvi 9th Social Science Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 9th Social Science History Solutions Chapter 1 Evolution of Humans and Society – Prehistoric Period

Evolution of Humans and Society – Prehistoric Period Textual Exercise

I. Choose the correct answer.

Question 1.
………….. is genetically closest to humans.
(a) Gorilla
(b) Chimpanzee
(c) Orang-utan
(d) Great Apes
Answer:
(b) Chimpanzee

Question 2.
The period called ……………. marks the beginning of agriculture and animal domestication.
(a) Palaeolithic
(b) Mesolithic
(c) Neolithic
(d) Megalithic
Answer:
(c) Neolithic

Question 3.
Direct ancestor of modem man was ……………..
(a) Homo habilis
(b) Homo erectus
(c) Homo sapiens
(d) Neanderthal man
Answer:
(c) Homo sapiens

Question 4.
………….. refers to the area covering Egypt, Israel-Palestine and Iraq.
(a) Great Rift Valley
(b) Fertile Crescent
(c) Solo river
(d) Neander Valley
Answer:
(b) Fertile Crescent

Question 5.
Sir Robert Bruce Foote, a geologist from England first discovered the …………. tools at Pallavaram near Chennai.
(a) Stone Age
(b) Palaeolithic
(c) Mesolithic
(d) Neolithic
Answer:
(b) Palaeolithic

Question 6.
(i) The period before the introduction of writing is called pre-history.
(ii) The pre-historic people developed language, made beautiful paintings and artefacts.
(iii) The pre-historic societies are treated as literate.
(iv) The pre-historic period is called ancient. .
(a) (i) is correct
(b) (i) and (ii) are correct
(c) (i) and (iv) are correct
(d) (ii) and (iii) are correct
Answer:
(c) (i) and (iv) are correct

Question 7.
(i) The Neolithic people used polished stone axes called Celts.
(ii) Evidence of Neolithic village is found at Payyampalli in Chennai district.
(iii) The cultural period that succeeded the Neolithic is called the Bronze Age.
(iv) The period that witnessed domestication .of animals and cultivation of crops is called Mesolithic.
(a) (i) is correct
(b) (ii) is correct
(c) (ii) and (iii) are correct
(d) (iv) is correct
Answer:
(a) (i) is correct

Question 8.
Assertion (A): Many of the Mesolithic sites are found nearby rivers and tanks.
Reason (R): Irrigation management developed during Mesolithic period.
(a) A and R are correct and R explains A
(b) A and R are correct but R doesn’t explain A
(c) A is correct but R is incorrect
(d) A and R both are incorrect
Answer:
(d) A and R both are incorrect

II. Fill in the blanks.

1. The primitive multi-cellular life first appeared in the age of ……………..
2. Hand axes and cleavers are important tool types of …………. culture.
3. The methods and techniques involved in the production of stone tools are called ………………… technology.
4. ………………. is known as the Middle Stone Age, as it is placed between the Palaeolithic and Neolithic.

Answers:

1. Proterozoic
2. Low Palaeolithic
3. Lithic
4. Mesolithic period

III. Find out the correct statement.

Question 1.
(a) The concept ‘survival of the fittest’ contributed to the scientific understanding of human origins.
(b) The book “On the Origin of Species” was published by Herbert Spencer.
(c) Darwin’s theory of biological evolution connects with the process of natural selection.
(d) Geology is the study of lithic technology.
Answer:
(a) correct
(b) incorrect
(c) correct
(d) incorrect

Question 2.
(a) Among the great Apes Orangutan is genetically the closest to humans.
(b) The ancestors of humans were called Hominins and their origins have been traced to Africa.
(c) Flake is a small chip that has flaking on both sides.
(d) Acheulian is the main block of stone from which small1 chips are flaked by using a hammerstone.
Answer:
(a) incorrect
(b) correct
(c) incorrect
(d) incorrect

IV. Match the following.

Answer:
1. (e)
2. (c)
3. (b)
4. (a)
5. (d)

V. Answer the following briefly.

Question 1.
Discuss how the age of speculation made humans become conscious and knowledgeable.
Answer:

1. Humans are the only species on earth concerned with understanding as well as explaining the world and the universe.
2. In the course of evolution, humans became conscious and knowledgeable.
3. They turned curious and began to think and ask questions about nature, organisms and the world around them.
4. They worshipped Sun, Moon and various natural forces about which they developed their own understanding, some of which is not scientific.

Question 2.
Write a note on the impact of pastoralism on the prehistoric people in Tamil Nadu.
Answer:

1. The people in the Age practiced agriculture, domesticated cattle and sheep.
2. Some of the groups were still hunting and gathering.
3. Millets & rice were cultivated.
4. Irrigation management developed in this period. In the deltaic regions irrigation as a technology had developed.
5. Evidences of rice is seen in Megalithic sites like Adidchanallur in Thoothukudi district and Porunthal near Palani.

Question 3.
List out the features of Megalithic Burial types.
Answer:

1. The Iron age is also known as megalithic since people created burials with large stones for the dead people.
2. Within these burials, the skeletons or few bones of the dead persons were placed along with grave goods including iron objects, Camelian beads, and bronze objects.
3. Some of the burials do not have human bones and they have only the grave goods.
4. They may be called memorial burials.

Question 4.
Examine the tool making technical skills of lower Palaeolithic people.
Answer:

1. Hand axes and cleavers are the important tool types of the Lower palaeolithic period.
2. These tools were fitted with a wooden and bone handle. They were used for cutting, piercing and digging.
3. The people also used hammer stones and spheroids.
4. The quartzite pebbles and cobbles were chosen as raw materials.
   The tools are found in the soil deposits and also in the exposed river side.

VI. Answer all the questions given under each caption.

Question 1.
Hominid and Hominins.
(a) Who are Hominids?
Answer:
Hominids refer to all the species of the modem and extinct great apes, which also includes humans.

(b) Who was the earliest human ancestor to make tools in Africa?
Answer:
Homo habilis (handy human) was the earliest known human ancestors to make tools in Africa about 2.6 million years ago.

(c) How are modern humans known?
Answer:
Modem-humans are known as Homo sapiens.

(d) Name any one species of this tribe.
Answer:
Homo erectus – extinct Humans are the only living species.

Question 2.
Earliest Lithic Assemblages of Human ancestors.
(a) Where are Acheulian tools reported to have been found in Karnataka and in Madhya Pradesh?
Answer:
Acheulian tools are reported to have been found in Isampur in Karnataka and Bhimbetka in Madhya Pradesh.

(b) What is meant by Lithic Technology?
Answer:
‘Lith’ means stone. The methods and techniques involved in the production of stone tools are called lithic technology.

(c) What are Biface tools?
Answer:
Bifaces are tools that have to flake on both sides (bi = two, face = side).

(d) Name a few stone tools used by human ancestors.
Answer:
Core is the main block of stone. Flake is a small chip removed from a large stone block. Levalloisian tools include long blades and burins. Burin is a stone-made chisel with a sharp cutting edge.

VII. Answer the following in detail.

Question 1.
The developments in the fields of agriculture, pottery, and metal tools are considered a landmark in the life of the Megalithic period- Substantiate.
Answer:
(a) Agriculture:

1. People practiced agriculture, domesticated cattle, and sheep.
2. Millets and rice were cultivated.
3. Irrigation management developed since many of the megalithic sites are found nearby rivers and tanks.
4. In the deltaic region, irrigation as technology had developed.
5. Evidence of rice is seen in the megalithic sites like Adichanallur in Thoothukudi district and Porunthal near Palani.

(b) Pottery:

1. Pottery is important evidence found in archaeological sites.
2. In the iron age and Sangam age people used black and red colours to make blackware and redware pottery.
3. Potteries were used for cooking, storage, and dining purposes.
4. The black and redware pottery has a black inside and a red outside, with lustrous surfaces.

(c) Metal tools:

1. Weapons such as swords and daggers, axes, chisels, lamps and tripod stands are also found.
2. The iron tools were used for agriculture, hunting and gathering and in battles.

Question 2.
The history of humans is closely related to the history of the earth. Elucidate.
Answer:

• The history of humans is closely related to the history of the earth.
• The earth contains geological, archaeological, and biological records of historical times in its upper layers.
• They are important for reconstructing the history of the earth and various living organisms.
• The fossil bones of the human ancestors are embedded in the earth’s layers.
• Palaeoanthropologists and archaeologists excavate the soil and rock layers on the earth and extract evidence about human ancestors.
• These layers and the fossils are scientifically dated to study the various stages in human evolution and prehistory.
• Through the gathered evidence they attempt to understand the evolution of human history and developments in chronological order.
• The earth was formed approximately 4.54 billion years ago.
• Gradually conditions emerged for the growth of organisms. Then plants and animals came into being and thereby foundation was laid for the evolution of humans. The long span of time in earth’s history is divided into eras, periods, and epochs by the Geologists. Thus the history of humans is closely related to the history of the earth.

Student Activities

Question 1.
Mark the prehistoric sites on the world map.
Answer:
(i) The ancestors of humans were called Hominins and their origins have been traced to Africa.
(ii) You can draw the Prehistoric sites of human ancestors in Africa with the guidance of your teacher.

Question 2.
Assignment with teacher’s guidance.
Answer:
A power-point presentation on the origin of human life.
A power-point presentation on the pre-historic tools.
A power-point presentation on the scripts of the ancient.

Evolution of Humans and Society – Prehistoric Period Additional Questions

I. Choose the correct answer.

1. …………….. is the study of the human past through the analysis and interpretation of material remains.
(a) Geology
(b) Archaeology
(c) History
(d) None of the above
Answer:
(b) Archaeology

Question 2.
The beginning of history writing can be traced to the ancient ……………..
(a) Greeks
(b) Egyptians
(c) Romans
(d) Africans
Answer:
(a) Greeks

Question 3.
The DNA of a Chimpanzee is ……………. identical to that of a human being.
(a) 95%
(b) 96%
(c) 97%
(d) 98%
Answer:
(d) 98%

Question 4.
………….. are stone artifacts of small size.
(a) Microliths
(b) Bifaces
(c) Acheulian
(d) core
Answer:
(a) Microliths

Question 5.
Evidence of Neolithic village is found at …………… in Vellore district.
(a) Gudiam
(b) Athirampakkam
(c) Payyampalli
(d) Salem
Answer:
(c) Payyampalli

Question 6.
The ……………. was a formative period and the foundation for the Sangam Age.
(a) Iron Age
(b) Bronze Age
(c) Stone Age
(d) Age of Information Technology
Answer:
(a) Iron Age

Question 7.
(i) We live in the age of Information Technology.
(ii) The internet has literally put the world at our fingertips.
(iii) The Prehistoric people were the pioneers of literacy.
(iv) Powerful Technology developed all of a sudden.
(a) (i) is correct
(b) (ii) & (iii) are correct
(c) (ii) & (iv) are correct
(d) (i) & (iii) are correct
Answer:
(a) (i) is correct

Question 8.
(i) The chimpanzee is genetically the closest to humans.
(ii) Hominins & their origin have been traced to Asia.
(iii) The Hominins emerged around 6 to 5 million years ago.
(iv) The Great Rift valley in Africa has many sites for the Prehistoric period.
(a) (i) is correct
(b) (ii) & (iii) are correct
(c) (i) & (iv) are correct
(d) (iii) is correct
Answer:
(a) (i) is correct and (c) (i) & (iv) are correct

Question 9.
……………… are tools used for scraping the surfaces.
(a) Lunates
(b) Triangles
(c) Scrapers
(d) Cists
Answer:
(c) Scrapers

Question 10.
…………… are pottery jars and were used for burying the dead.
(a) Urns
(b) Cists
(c) Dolmens
(d) Menheirs
Answer:
(a) Urns

II. Fill in the blanks.

1. Prehistoric people were the pioneers of ……………..
2. ………….. were the apes from which modem humans evolved.
3. A prehistoric animal (or) plant that turns to stone over a period of time …………….
4. The earliest tools made by human ancestors are found in ……………. in Kenya.
5. …………….. people buried the dead people systematically.
6. Rice was probably cultivated in India and China around …………… (or) even earlier.
7. Oxen were used in ………….. civilisation for tilling the land.
8. ……………. discovered the first Palaeolithic tools in India at Pallavaram.
9. …………. people perhaps devised the first pottery.
10. The black and Red colour pottery were used by ……………. and people.

Answers:

1. Creative Knowledge
2. Australopithecines
3. Fossil
4. Lomekwi
5. Neanderthals
6. 7000 BCE
7. Sumerian
8. Sir Robert Bruce Foote
9. Neolithic
10. Iron Age & Sangam Age

III. Match the following

a.

Answer:

1. (d)
2. (e)
3. (a)
4. (b)
5. (c)

b.

Answer:

1. (d)
2. (e)
3. (a)
4. (b)
5. (c)

IV. Answer the following briefly.

Question 1.
Discuss when the earth was formed.
Answer:

1. The earth was formed approximately 4.54 billion years ago.
2. Gradually, conditions emerged for the growth of organisms.
3. Then plants and animals came into being and thereby foundation was laid for the evolution of humans.
4. The long span of time in earth’s history is divided into eras periods and epochs by the geologists.

Question 2.
Who proposed the idea of the Three Age system?
Answer:

1. The idea of the Three Age system proposed by CJ. Thomsen became the basis for understanding early human history.
2. He classified the artifacts in the Danish National Museum, Copenhagen, into Stone Age, Bronze Age, and Iron Age.

Question 3.
The Great Rift valley in Africa has evidence for the Prehistoric period. Discuss.
Answer:

• The Great Rift valley in Africa has many sites that have evidence for the prehistoric period.
• The Great Rift valley is a valley-like formation that runs for about 6,400 km from the Northern part of Syria to Central Mozambique in East Africa.
• This geographical feature is visible even from space, and many prehistoric sites are found in Africa.

Question 4.
Write a short note on “Prehistoric cultures”.
Answer:
While the fossil bones are classified as various species such as Homo habilis, Homo erectus, and Neanderthalensis, based on the lithic tools, cultures are assigned names such as Earliest Lithic, Assemblages, Oldowan Technology, Lower, Middle and Upper Palaeolithic, and Mesolithic cultures.

Question 5.
Why were the Levalloisian tools called so?
Answer:

1. The lithic tool-making tradition of the Levalloisian belonged to this period.
2. Levalloisian tools are the implements made after preparing the core.
3. These tools are found in Europe and Central and Western Asia.
4. The Levalloisian tools are the implements made after preparing the core. It was named after the town of Levallois in France.

Question 6.
What was the main factor for the development of early civilisations?
Answer:

1. As a result of domestication and cultivating plants, there was excess food production.
2. The surplus food production was the main factor for the development of early civilizations.

Question 7.
Describe the burials in the Sangam Age.
Answer:

1. The Sangam literature mentions the various burial practices of the people.
2. The Megalithic burials are classified as dolmens, cists, menheirs, rock-cut caves, um burials, and sarcophagus.
3. The burial types of Kodakkal (umbrella stone), Toppikkal (hot stone), and Paththikal (hood stone) are found in Kerala.

V. Answer all the questions given under each caption.

(A) Oldest Museum.
Question 1.
Name the oldest museum, in the world.
Answer:
The museum of Ennigaldi Nanna in Mesopotamia.

Question 2.
When was it established?
Answer:
It was established in 530 BCE.

Question 3.
Which is the oldest surviving museum at present?
Answer:
The Capitoline museum in Italy is perhaps the oldest surviving museum at present (1471 CE).

Question 4.
Name the oldest university museum in the world.
Answer:
Ashmolean Museum at Oxford University is the oldest University Museum in the world.

(B) Mesolithic culture.
Question 1.
Mention the evidence for the existence of Mesolithic hunt-gatherers.
Answers:
They are found at Chennai, North Arcot, Dharmapuri, Salem, Coimbatore, Ariyalur, Trichi, Pudukottai, Madurai, Sivagangai, Tirunelveli, and Kanyakumari.

Question 2.
What type of artifacts were used by the people of this period?
Answer:
The people of this period used small artifacts made of Chert and Quartz. .

Question 3.
What are the tool types used by them?
Answer:
The tool types are scrapers, lunates, and triangles.

Question 4.
What did they do for their subsistence?
Answer:
These people hunted wild animals and gathered fruits, nuts, and roots for their subsistence.

VI. Answer the following in detail.

Question 1.
Discuss the Neolithic culture in Tamilnadu.
Answer:

• The culture that domesticated animals and cultivated crops is called Neolithic.
• It is known as the New Stone Age. The Neolithic people used polished stone axes called celts.
• Cattle rearing was their main occupation. They lived in small villages with houses made of thatched roof and walls plastered with clay.
• Evidence of Neolithic village is found at Payyampalli in Vellore district and a few sites in the Dharmapuri region.
• Payyampalli is a village in the Vellore district of Tamil Nadu. The earliest evidence for the domestication of animals and the cultivation of plants is found at this site, which was excavated by the Archaeological Survey of India.
• Evidence for pottery making and cultivation of horse gram and green gram has been found in this village.
• These Neolithic sites were part of the Southern Neolithic Culture of India. They are mainly concentrated in the Andhra Pradesh and Karnataka regions.
• The Neolithic people used stone axes fitted on a wooden handle.
• These polished stone axes are worshipped in many village temples of Tamil Nadu even today.

Question 2.
Domestication of Animals and plants. A milestone in Human History. Explain.
Answer:

1. Rice was probably cultivated in India and China around 7000 BCE or even earlier.
2. Wheat and barley were cultivated at Mehrgarh in the northwestern part of the Indian subcontinent (Pakistan) before 6000 BCE.
3. Animal domestication developed as part of symbiotic life.
4. Dogs may have been domesticated first. Friendly animals were gradually domesticated. Sheep and goat were domesticated around 10,000 BCE in Southwest Asia.
5. Oxen were used in Sumerian civilization for tilling the land. Mehrgarh in Pakistan has evidence of sheep, goat, and cattle domestication in the Neolithic period.

You can Download Samacheer Kalvi 9th Social Science Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 9th Social Science Civics Solutions Chapter 4 Forms of Government

Forms of Government Textual Exercise

I. Fill in the blanks.

1. ……… are the few examples of the unitary form of government.
2. The Parliamentary government is also known as ……..
3. In the parliamentary form of government ….. is the leader of the majority party.

Answers:

1. England, France
2. cabinet government
3. Prime Minister

II. Fill in the blanks.

Question 1.

Country	Name of the Parliament
USA	…………..
Norway	…………..
…………	Folketing

Answer:

Country	Name of the Parliament
USA	Congress
Norway	Storting
Denmark	Folketing

III. Distinguish Between.

Question 1.
Unitary and federal forms of government.
Answer:

Unitary form of government	The federal form of government
Only one Level of Government or Subunits	Two Levels of Government
Mostly Single Citizenship	Dual Citizenship
Sub Units cannot operate independently	Federal Units are answerable to Central Government
No Division of Power	Division of Power
Centralization of Power	Decentralization of Power

Question 2.
Parliamentary and presidential form of government.
Answer:

Parliamentary form of government	Presidential form of government
Majority Party Rules	The President is elected by an electoral college for a fixed tenure of four years.
Collective Responsibility	The President governs with the help of a cabinet or a smaller body called ‘Kitchen Cabinet’.
The leadership of the Prime Minister	The President is both the head of the State and the head of government.

IV. Give a short note on:

Question 1.
Unitary form of government
Answer:

1. A unitary system of government or unitary state is a sovereign state governed as a single entity.
2. The Central government is supreme.
3. The administrative divisions exercise only powers that the central government has delegated to them.
4. England, France, Japan, Sri Lanka are examples of a unitary form of governments.

V. Answer the following.

Question 1.
List out the types of constitution.
Answer:

Question 2.
What are the merits of a federal government?
Answer:
Merits of federal form of government

• Reconciliation of local autonomy with national unity.
• Division of power between centre and states leads to administrative efficiency.
• It gives rise to big states
• Distribution of powers check the despotism of central government.
• More suitable for bigger countries.
• It is good for economic and cultural progress.

Question 3.
Write down the differences between the unitary form of government and the federal form of
government.
Answer:

Unitary form of government	The federal form of government
Only one Level of Government or Subunits	Two Levels of Government
Mostly Single Citizenship	Dual Citizenship
Sub Units cannot operate independently	Federal Units are answerable to Central Government
No Division of Power	Division of Power
Centralisation of Power	Decentralisation of Power

VI. Answer in detail.

Question 1.
Write about the merits of a unitary form of government.
Answer:
Merits of a unitary form of government

1. Suitable for small countries.
2. There is no conflict of authority and responsibility.
3. A unitary government will make prompt decisions and take speedy action.
4. A unitary government is less expensive.
5. Amendments to the constitution are easy.
6. There is unity, uniformity of law, policy, and administration.

Question 2.
Write about the presidential form of government and what is the difference between presidential and parliamentary forms of government.
Answer:
The Presidential Form Of Government is also known as a non-responsible or non-parliamentary or fixed executive system of government, basically built on the principle of separation of power and is prevalent in the USA, Brazil, Russia, and Sri Lanka among others.

The American President is both the head of the State and the head of government. As the head of State, he occupies a ceremonial position. As the head of government, he leads the executive organ of the government.

The President is elected by an electoral college for a fixed tenure of four years. He cannot be removed by the Congress, except by impeachment for a grave unconstitutional act.

The President governs with the help of a cabinet or a smaller body called ‘Kitchen Cabinet’. It is only an advisory body and consists of non-elected departmental secretaries. They are selected and appointed by him, are responsible only to him, and can be removed by him at any time.

The President and his secretaries are not responsible to Congress for their acts. They neither possess membership in the Congress nor attend its sessions.

Differences between presidential and parliamentary forms of government are:

Parliamentary form of government	Presidential form of government
Prime Minister is from the majority party	President is directly elected by the People
Central Legislature is supreme	President is Supreme
Absence of Separation Powers Centralisation	Separation of Powers
Independent branches with Overlapping functions	Independent branches
President – Head of the State	President – Head of the State
Prime Minister – Head of the Government	President – Head of the Government
Collective leadership	Individual Leadership
Collective and Individual Responsibility	President is not accountable to Congress

Forms of Government Additional Questions

I. Fill in the blanks.

1. ……. is the main agency of the state.
2. The three organs in government are …….., ………, and ……….
3. ……… is the oldest form of government in the United Kingdom.
4. An example of Federal form of Government ……..
5. The …… system of government is the one in which the executive is responsible to the legislature for its policies and acts.
6. The …… form of government is prevalent in the U.S.A.
7. The President governs with the help of a cabinet (or) a small body called …… in the Presidential form of government.
8. An unprecedented development forced the ……… to step down and paved the way for Democracy.
9. Gross National Happiness was first mentioned in the constitution of Bhutan, which was enacted on ……
10. …… and …….. are synonyms, both denoting the exercise of authority in an organization, institution (or) state.
Answers:
1. Government
2. legislature, executive, judiciary
3. Monarchy
4. Argentina
5. Parliamentary
6. Presidential
7. Kitchen Cabinet
8. King Gyanendra.
9. 18^th July 2008
10. Government, Governance

II. Fill up.

Country	Name of the Parliament
Israel	……………………..
	Bundestag

Answer:

Country	Name of the Parliament
Israel	Knesset
Germany	Bundestag

III. Distinguish the following:

Question 1.
Monarchy and Democracy
Answer:

Monarchy	Democracy
A form of movement with a Monarch as the head.	The government is headed by elected representatives.
Power is passed through heritage and bloodline.	This principally supports the election.

IV. Answer the following.

Question 1.
What is the meaning of Government?
Answer:
‘Government’ refers to the executive functions of the state. It denotes a body having authority to make and enforce laws applicable to the civil, corporate, religious, academic of other groups.

Question 2.
From where did the term Government was derived?
Answer:
The term Government is derived from Old French ‘governer’, derived from Latin ‘gubernare’ to direct, rule, guide, govern”.

Question 3.
Mention the demerits of Unitary form of Government.
Answer:

• It is not suitable for big countries.
• The central government will have to tackle so many complex problems that lead to administrative delay
• The central government will not concentrate on local problems, local interest and initiative.
• The concentration of powers may pave way for the despotism of the central government.

Question 4.
State the feature of the Parliamentary form of governance.
Answer:
Features of parliamentary form of government

• Nominal and Real Executives
• Majority Party Rule
• Collective Responsibility
• Dual Membership
• The leadership of the Prime Minister

Question 5.
State the merits of the Presidential system of government.
Answer:
Merits of the presidential system of government

• Democratic
• Effective Control by the President
• Facilitate decision-making
• State government

Question 6.
Write down the characteristics of good governance.
Answer:
Characteristics of good governance:

• Participation
• Rule Of Law
• Transparency
• Responsiveness
• Consensus Orientation
• Equity
• Effectiveness And Efficiency
• Accountability

V. Answer in detail.

Question 1.
Explain the Federal form of Government.
Answer:
The classification of governments into unitary and federal is based on the nature of relations between the national and the regional governments.

A federal government is one in which powers are divided between the national government and the regional governments by the Constitution itself and both operate in their respective jurisdictions independently. U.S.A, Switzerland, Australia, Canada, Russia, Brazil, Argentina have federal form of governments. In a federal model, the national government is known as the Federal government or the Central Government or the Union government and the regional government is known as the state government or the provincial government.

Merits of federal form of government

• Reconciliation of local autonomy with national unity
• Division of power between centre and states leads to administrative efficiency
• It gives rise to big states
• Distribution of powers check the despotism of central government
• More suitable for bigger countries
• It is good for economic and cultural progress

De-merits of federal form of government

• Federal government is weaker when compared to the unitary government.
• Federal government is more expensive
• Provincial tendencies are very common
• Lack of uniformity in Administration
• Threat to national unity
• Distribution of powers between centre and states lead to conflicts
• Double Citizenship
• Rigid constitution cannot be mended easily for changing needs
• The state governments sometimes place hindrances in foreign policy.

Federal features of the Indian constitution

• Dual Government
• Written Constitution
• Division of Powers
• Supremacy of the Constitution. The Constitution is the supreme law of the land.
• The laws enacted by the Centre and the states must confirm to its provisions.
• Rigid Constitution
• Independent Judiciary
• Bicameralism

Question 2.
Explain Gross National Happiness.
Answer:
Gross National Happiness is a developing philosophy as well as an ‘index’ which is used to measure the collective happiness in any specific nation. The concept was first mentioned in the constitution of Bhutan, which was enacted on 18 July 2008.

The term ‘Gross National Happiness’ was coined by the fourth king of Bhutan, Jigme Singye Wangchuck, in the 1970s. The GNH’s central tenets are “Sustainable and equitable socio-economic development; environmental conservation; preservation and promotion of culture; and good governance”. GNH is distinguishable by valuing collective happiness as the goal of governance and by emphasising harmony with nature and traditional values.

You can Download Samacheer Kalvi 10th Science Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 5 Acoustics

Samacheer Kalvi 10th Science Acoustics Textual Solved Problems

Question 1.
At what temperature will the velocity of sound in the air be double the velocity of sound in air at 0° C?
Solution:
Let T° C be the required temperature. Let v₁ and v₂ be the velocity of sound at temperatures T₁K and T₂K respectively.
T₁ = 273K (0°C) and T₂ = (T°C + 273)K
\(\frac{v_{2}}{v_{1}}=\sqrt{\frac{\mathrm{T}_{2}}{\mathrm{T}_{1}}}=\sqrt{\frac{273+\mathrm{T}}{273}}=2\)
Here, it is given that, v₂/v₁ = 2
So \(\frac{273+\mathrm{T}}{273}=4\)
T = (273 × 4) – 273 = 819° C.

Question 2.
A source producing a sound of frequency 90 Hz is approaching a stationary listener with a speed equal to (1 / 10) of the speed of sound. What will be the frequency heard by the listener?
Solution:
When the source is moving towards the stationary listener, the expression for apparent frequency is
\(n^{\prime}=\left(\frac{v}{v-v_{s}}\right) n\)
\(\begin{array}{l}{=\left(\frac{v}{v-\left(\frac{1}{10}\right) v}\right) n=\left(\frac{10}{9}\right) n} \\ {=\left(\frac{10}{9}\right) \times 90=100 \mathrm{Hz}}\end{array}\)

Question 3.
A source producing a sound of frequency 500 Hz is moving towards a listener with a velocity of 30 ms^-1. The speed of the sound is 330 ms^-1. What will be the frequency heard by the listener?
Solution:
When the source is moving towards the stationary listener, the expression for apparent frequency is
n’ = \(\left(\frac{v}{v-v_{\mathrm{s}}}\right) n\)
= \(\left(\frac{330}{330-30}\right) \times 500\)
= 550 Hz.

Question 4.
A source of sound is moving with a velocity of 50 ms^-1 towards a stationary listener. The listener measures the frequency of the source as 1000 Hz. what will be the apparent frequency of the source when it is moving away from the listener after crossing him? (velocity of sound in the medium is 330 ms^-1)
Solution:
When the source is moving towards the stationary listener, the expression for apparent frequency is
\(\begin{aligned} n^{\prime} &=\left(\frac{v}{v-v_{\mathrm{s}}}\right) n \\ 1000 &=\left(\frac{330}{330-50}\right) n \\ n &=\left(\frac{1000 \times 280}{330}\right) \end{aligned}\)
n = 848.48 Hz.
The actual frequency of the sound is 848.48 Hz. When the source is moving away from the stationary listener, the expression for apparent frequency is
\(\begin{aligned} n^{\prime} &=\left(\frac{v}{v+v_{\mathrm{s}}}\right) n \\ &=\left(\frac{330}{330+50}\right) \times 848.48 \end{aligned}\)
= 736.84 Hz.

Question 5.
A source and listener are both moving towards each other with a speed v/10 where v is the speed of sound. If the frequency of the note emitted by the source is f, what will be the frequency heard by the listener?
Solution:
When source and listener are both moving towards each other, the apparent frequency is
\(\begin{aligned} n^{\prime} &=\left(\frac{v+v_{l}}{v-v_{s}}\right) n \\ n^{\prime} &=\left(\frac{v+\frac{v}{10}}{v-\frac{v}{10}}\right) n \\ n^{\prime} &=\frac{11}{9} \cdot f \\ &=1.22 f \end{aligned}\)

Question 6.
At what speed should a source of sound move away from a stationary observer so that the observer finds the apparent frequency equal to half of the original frequency?
Solution:
When the source is moving away from the stationary listener, the expression for the apparent frequency is
\(\begin{array}{l}{n^{\prime}=\left(\frac{v}{v+v_{\mathrm{s}}}\right) n} \\ {\frac{n}{2}=\left(\frac{v}{v+v_{\mathrm{s}}}\right) n} \\ {v_{\mathrm{s}}=v}\end{array}\)

Samacheer Kalvi 10th Science Acoustics Textual Evaluation

I. Choose the best Answer

Question 1.
When a sound wave travels through air, the air particles _____.
(a) vibrate along the direction of the wave motion
(b) vibrate but not in any fixed direction
(c) vibrate perpendicular to the direction of the wave motion
(d) do not vibrate.
Answer:
(a) vibrate along the direction of the wave motion

Question 2.
Velocity of sound in a gaseous medium is 330 ms^-1. If the pressure is increased by 4 times without causing a change in the temperature,
the velocity of sound in the gas is:
(a) 330 ms^-1
(b) 660 ms¹
(c) 156 ms^-1
(d) 990 ms^-1
Answer:
(a) 330 ms^-1

Question 3.
The frequency, which is audible to the human ear is _____.
(a) 50 kHz
(b) 20 kHz
(c) 15000 kHz
(d) 10000 kHz.
Answer:
(b) 20 kHz
Hint: Audible frequency hearing the human ear range between 20 Hz to 20 kHz

Question 4.
The velocity of sound in air at a particular temperature is 330 ms^-1. What will be its value when temperature is doubled and the pressure is halved?
(a) 330 ms^-1
(b) 165 ms^-1
(c) 330 × √2 ms^-1
(d) 320 × √2 ms^-1
Answer:
(a) 330 ms^-1

Question 5.
If a sound wave travels with a frequency of 1.25 × 10⁴ Hz at 344 ms^-1, the wavelength will be _____.
(a) 27.52 m
(b) 275.2 m
(c) 0.02752 m
(d) 2.752 m.
Answer:
(c) 0.02752 m
Hint: Velocity of sound = frequency × wavelength
v = nλ
\(\lambda=\frac{v}{n}=\frac{344}{1.24 \times 10^{4}}\)
λ = 0.02752 m.

Question 6.
The sound waves are reflected from an obstacle into the same medium from which they were incident. Which of the following changes?
(a) speed
(b) frequency
(c) wavelength
(d) none of these.
Answer:
(d) none of these.
Hint: If there is the same medium of a reflected obstacle is used, there is no change in speed, frequency and wavelength of the sound.

Question 7.
Velocity of sound in the atmosphere of a planet is 500 ms^-1. The minimum distance between the sources of sound and the obstacle to hear the echo, in point Is is:
(a) 17 m
(b) 20 m
(c) 25 m
(d) 50 m
Answer:
(c) 25 m

II. Fill in the blanks

Question 1.
The rapid back and forth motion of a particle about its mean position is called _____.
Answer:
vibrations.

Question 2.
If the energy in a longitudinal wave travels from south to north, the particles of the medium would be vibrating in _____.
Answer:
both north and south.

Question 3.
A whistle giving out a sound of frequency 450 Hz, approaches a stationary observer at a speed of 33 ms^-1. The frequency heard by the observer is (speed of sound = 330 ms^-1) ______.
Answer:
Data:
v = 330 ms^-1
v_S = 33 ms^-1
n = 450 Hz
n’ =?
Apparent frequency
\(\begin{aligned} n^{\prime} &=\left(\frac{v}{v-v_{\mathrm{S}}}\right) n \\ &=\left(\frac{330}{330-33}\right) \times 450=1.11 \times 450 \end{aligned}\)
n’ = 500 Hz.

Question 4.
A source of sound is travelling with a velocity 40 km/h towards an observer and emits a sound of frequency 2000 Hz. If the velocity of sound is 1220 km/h, then the apparent frequency heard by the observer is _____.
Answer:
2068 Hz
Hint: Apparent frequency heard by the observer.
Data:
v = 1220 km/h (or) 339 ms^-1
v_S = 40 km/h (or) 11.1 ms^-1
n = 2000 Hz
\(\begin{aligned} n^{\prime} &=\left(\frac{v}{v-v_{\mathrm{s}}}\right) n \\ &=\left(\frac{339}{339-11.1}\right) \times 2000 \end{aligned}\)
= 1.03385 × 2000
n’ = 2068 Hz.

III. True or False. If false give the reason

Question 1.
Sound can travel through solids, gases, liquids and even vacuum.
Answer:
False.
Reason: Sound can not travel in a vacuum. This is because sound waves are vibrating waves. In vacuum, where there are no atoms or molecules to vibrate.

Question 2.
Waves created by Earth Quake are Infrasonic.
Answer:
True.

Question 3.
The velocity of sound is independent of temperature.
Answer:
False.
Reason: For an ideal gas the velocity of sound depends on its temperature and is independent of gas pressure.

Question 4.
The velocity of sound is high in gases than liquids.
Answer:
False.
Reason: Velocity of a sound wave is maximum in solids because they are more elastic in nature than liquids and gases. Since gases are least elastic in nature, the velocity of sound is the least in a gaseous medium.
So V_S > V_L > V_G.

IV. Match the following

Question 1.

1. Infrasonic	(a) Compressions
2. Echo	(b) 22 kHz
3. Ultrasonic	(c) 10 Hz
4. High-pressure region	(d) Ultrasonography

Answer:
1. (c) 10 Hz
2. (d) Ultrasonography
3. (b) 22 kHz
4. (a) Compressions

V. Assertion and Reason Type Questions

Mark the correct choice as
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true but the reason is not the correct explanation of the assertion.
(c) The assertion is true, but the reason is false.
(d) The assertion is false, but the reason is true.

Question 1.
Assertion: The change in air pressure affects the speed of sound.
Reason: The speed of sound in a gas is proportional to the square of the pressure
Answer:
(d) The assertion is false, but the reason is true.

Question 2.
Assertion: Sound travels faster in solids than in gases.
Reason: Solid posses a greater density than that of gases.
Answer:
(b) If both the assertion and the reason are true but the reason is not the correct explanation of the assertion.

VI. Answer very briefly

Question 1.
What is a longitudinal wave?
Answer:
If the particles of the medium vibrate along the direction of propagation of the wave.

Question 2.
What is the audible range of frequency?
Answer:
Audible range of frequency is from 20 Hz to 20000 Hz.

Question 3.
What is the minimum distance needed for an echo?
Answer:

1. The minimum distance required to hear an echo is 1/20th part of the magnitude of the velocity of sound in air.
2. If you consider the velocity of sound as 344 ms^-1, the minimum distance required to hear an echo is 17.2 m.

Question 4.
What will be the frequency sound having 0.20 m as its wavelength, when it travels with a speed of 331 m s^-1?
Answer:
Speed v = 331 m/s
Let the wave length be λ = 0.2 m
Let the frequency be n
∴ Frequency n = \(\frac{v}{λ}\) = \(\frac{331}{0.2}\) = \(\frac{3310}{2}\)
∴ Frequency = 1655 Hz

Question 5.
Name three animals, which can hear ultrasonic vibrations.
Answer:
Mosquitos, bats and dogs are the three animals that can hear ultrasonic vibrations.

VII. Answer briefly

Question 1.
Why does sound travel faster on a rainy day than on a dry day?
Answer:
When humidity increases, the speed of sound increases. That is why you can hear sound from long distances clearly during rainy seasons.

Question 2.
Why does an empty vessel produce more sound than a filled one?
Answer:
In an empty vessel, multiple reflections of sound takes place. Hence more sound is produced in an empty vessel than tilled one.

Question 3.
Air temperature in the Rajasthan desert can reach 46°C. What is the velocity of sound in air at that temperature? (v₀ = 331 ms^-1)
Answer:
Velocity of sound, v₀ = 331 ms^-1
Air temperature, T = 46° C
Velocity of sound in air temperature v_T = (v₀ + 0.61T) ms^-1
= 331 + (0.61 × 46)
= 331 + 28.06
v_T = 359.06 ms^-1.

Question 4.
Explain why the ceilings of concert halls are curved.
Answer:
The ceilings of concert halls are curved so that multiple reflections of sound waves can take place.
The parabolic surfaces are used to focus the sound at a particular point. Hence sound will be louder.

Question 5.
Mention two cases in which there is no Doppler effect in sound?
Answer:

1. When source (S) and listener (L) both are at rest.
2. When S and L move in such a way that distance between them remains constant.
3. When source S and L are moving in mutually perpendicular directions.
4. If the source is situated at the centre of the circle along which the listener is moving.

VIII. Problem Corner

Question 1.
A sound wave has a frequency of 200 Hz and a speed of 400 ms^-1 in a medium. Find the wavelength of the sound wave.
Solution:
A sound wave of frequency, n = 200 Hz
Speed, v = 400 ms^-1
The wavelength of the sound wave, λ = \(\frac{v}{n}\)
λ = \(\frac{400}{200}\) = 2 m.

Question 2.
The thunder of cloud is heard 9.8 seconds later than the flash of lightning. If the speed of sound in air is 330 ms^-1, what will be the height of the cloud?
Answer:
Speed of sound in air v = 330 m/s
Time to hear thunder t = 9.8 s
∴ Height of the cloud = v × t
= 330 × 9.8
= 3234 m.

Question 3.
A person who is sitting at a distance of 400 m from a source of sound is listening to a sound of 600 Hz. Find the time period between successive compressions from the source?
Solution:
Frequency = \(\frac{1}{\text { Time period }}\)
Time period = \(\frac{1}{\text { Frequency }}=\frac{1}{600}\)
T = 0.00167 seconds
The time period between successive compressions from the source is 0.00167 seconds.

Question 4.
An ultrasonic wave is sent from a ship towards the bottom of the sea. It is found that the time interval between the transmission and reception of the wave is 1.6 seconds. What is the depth of the sea, if the velocity of sound in the seawater is 1400 ms^-1?
Solution:

The depth of the sea is 1120 m.

Question 5.
A man is standing between two vertical walls 680 m apart. He claps his hands and hears two distinct echoes after 0.9 seconds and 1.1 seconds respectively. What is the speed of sound in the air?
Solution:
Given data is
d = 680 m
t₁ = 0.9 s
t₂ = 1.1 s
v = ?
\(\text { Velocity }=\frac{\text { Distance travelled by sound }}{\text { Time taken }}\)
\(v=\frac{2 d}{t}\)

Question 6.
Two observers are stationed in two boats 4.5 km apart. A sound signal sent by one, under water, reaches the other after 3 seconds. What is the speed of sound in the water?
Answer:
Distance of boats d = 4.5 × 10³ m
= 4500 m.
Time t = 3 s
Speed of sound in water = \(\frac{d}{t}\)
= \(\frac{4500}{3}\)
= 1500 m/s

Question 7.
A strong sound signal is sent from a ship towards the bottom of the sea. It is received back after 1 s What is the depth of sea given that the speed of sound in water 1450 ms^-1?
Solution:
Velocity of sound in water \(=\frac{\text { Distance travelled by sound }}{\text { Time taken }}\)
Depth of the sea, d = velocity × time
\(d=\frac{v t}{2}=\frac{1450 \times 1}{2}\) = 725 m.

IX. Answer in Detail

Question 1.
What are the factors that affect the speed of sound in gases?
Answer:
In the case of gases, the following factors affect the velocity of sound waves.
Effect of density : The velocity of sound in a gas is inversely proportional to the square root of the density of the gas. Hence, the velocity decreases as the density of the gas increases.
v ∝\(\sqrt{\frac{1}{d}}\)

Effect of temperature : The velocity of sound in a gas is directly proportional to the square root of its temperature. The velocity of sound in a gas increases with the increase in temperature v ∝ √T. Velocity at temperature T is given by the following equation:
V_r = (v_o + 0.61 T)ms^-1.
Here, v_o is the velocity of sound in the gas at 0° C. For air, v_o = 331 ms^-1. Hence, the velocity of sound changes by 0.61 ms^-1 when the temperature changes by one degree Celsius.

Effect of relative humidity : When humidity increases, the speed of sound increases. That is why you can hear sound from long distances clearly during rainy seasons.

Question 2.
What is mean by the reflection of sound? Explain.
Answer:
Reflection of Sound:
The bouncing of sound waves from the interface between two media is termed as the reflection of sound.
(a) Reflection at the boundary of a rarer medium

• Consider a wave travelling in a solid medium striking on the interface between the solid and the air. The compression exerts a force F on the surface of the rarer medium.
• As a rarer medium has smaller resistance for any deformation, the surface of separation is pushed backwards.
• As the particles of the rarer medium are free to move, a rarefaction is produced at the interface. Thus, compression is reflected as rarefaction and a rarefaction travels from right to left.

(b) Reflection at the boundary of a denser medium

• A longitudinal wave travels in a medium in the form of compressions and rarefactions. Suppose a compression travelling in the air from left to right reaches a rigid wall.
• The compression exerts a force F on the rigid wall. In turn, the wall exerts an equal and
  opposite reaction R = -F on the air molecules. This results in a compression near the rigid wall.
• Thus, a compression travelling towards the rigid wall is reflected back as a compression. That is the direction of compression is reversed.

(c) Reflection at sound in curved surfaces

• When the sound waves are reflected from the curved surfaces, the intensity of the reflected waves is changed.
• When reflected from a convex surface, the reflected waves are diverged out and the intensity is decreased.
• When sound is reflected from a concave surface, the reflected waves are converged and focused at a point. So the intensity of reflected waves is concentrated at a point.
• Parabolic surfaces are used when it is required to focus the sound at a particular point. Hence, many halls are designed with parabolic reflecting surfaces.
• In elliptical surfaces, sound from one focus will always be reflected the other focus, no matter where it strikes the wall.

Question 3.
(a) What do you understand by the term ‘ultrasonic vibration’?
(b) State three uses of ultrasonic vibrations.
(c) Name three animals which can hear ultrasonic vibrations.
Answer:
(a) Ultrasonic vibrations are the vibration with frequency greater than 20 KHz. Human ear cannot detect the ultrasonic vibration.

(b) (i) Ultrasonic waves are used in ultrasonography.
(ii) It is used to get signal images of a developing embryo in the mother’s uterus.
(in) They are used to forecast about tsunami and earthquake.

(c) Certain creatures like dog, bats, dolphins and mosquito can detect the waves.

Question 4.
What is an echo?
(a) State two conditions necessary for hearing an echo.
(b) What are the medical applications of echo?
(c) How can you calculate the speed of sound using echo?
Answer:
Echo: An echo is the sound reproduced due to the reflection of the original sound from various rigid surfaces such as walls, ceilings, surfaces of mountains, etc.

(a) (i) The persistence of hearing for human ears is 0.1 second. This means that we can hear two sound waves clearly if the time interval between the two sounds is at least 0.1 s. Thus, the minimum time gap between the original sound and an echo must be 0.1 s.

(ii) The above criterion can be satisfied only when the distance between the source of the sound and the reflecting surface would satisfy the following equation:
\(\begin{aligned} \text { Velocity } &=\frac{\text { Distance travelled by sound }}{\text { Timetaken }} \\ v &=\frac{2 d}{t} \\ d &=\frac{v t}{2} \end{aligned}\)
Since, t = 0.1 second, then \(d=\frac{v \times 0.1}{2}=\frac{v}{20}\)

(b) (i) The principle of echo is used in obstetric ultrasonography, which is used to create real – time visual images of the developing embryo or fetus in the mother’s uterus.
(ii) This is a safe testing tool, as it does not use any harmful radiations.

(c) Apparatus required:
A source of sound pulses, a measuring tape, a sound receiver and a stopwatch.
Calculation of speed of sound:
The sound pulse emitted by the source travels a total distance of 2nd while travelling from the source to the wall and then back to the receiver.
The time taken for this has been observed to be ‘t’. Hence, the speed of the sound wave is given by:
\(\text { Speed of sound }=\frac{\text { Distance travelled }}{\text { Timetaken }}=\frac{2 d}{t}\).

X. HOT Questions

Question 1.
Suppose that a sound wave and a light wave have the same frequency, then which one has a longer wavelength?
(a) Sound
(b) Light
(c) both (a) and (b)
(d) data not sufficient.
Answer:
(b) light
Explanation: The light wave has a longer wavelength because it has much greater speed.

Question 2.
When sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound remain the same. Do you hear an echo sound on a hotter day? Justify your answer.
Answer:
Echo of sound is heard with less velocity and intensity on a hotter day. Because the velocity of sound is directly proportional to temperature of air. On a hotter day temperature will be higher so velocity of sound will be changed by higher values.

Samacheer Kalvi 10th Science Acoustics Additional Questions

I. Choose the best answer

Question 1.
Light can travel in a vacuum but not sound because of ______.
(a) speed of sound is very slow than light.
(b) light waves are electromagnetic in nature.
(c) sound waves are electromagnetic in nature.
(d) light waves are not electromagnetic in nature.
Answer:
(a) speed of sound is very slow than light.
Hint: Light can travel in a vacuum because light waves are electromagnetic in nature.

Question 2.
In a longitudinal wave there is a state of maximum compression at a point at an instant. The frequency of wave is 50 Hz. After what time will the same point be in the state of maximum rarefaction:
(a) 50 s
(b) 25 s
(c) 0.01 s
(d) 0.002 s
Answer:
(c) 0.01 s

Question 3.
When sound travels from air to water, which parameter does not change?
(a) Wavelength
(b) Frequency
(c) Velocity
(d) Temperature.
Answer:
(b) Frequency
Hint: Frequency remains unchanged when sound travels from air to water.

Question 4.
When a wave passes from one medium to another, there is a change of:
(a) Wavelength and velocity
(b) Wavelength and frequency
(c) Velocity and frequency
(d) Velocity only
Answer:
(a) Wavelength and velocity

Question 5.
At what temperature, the speed of sound in the air will become double of its value at 27°C?
(a) 54° C
(b) 627° C
(c) 327° C
(d) 927° C.
Answer:
(d) 927° C.
Hint:
\(\frac{v_{1}}{v_{2}}=\sqrt{\frac{\mathrm{T}_{1}}{\mathrm{T}_{2}}} \Rightarrow \frac{v_{1}}{2 v_{1}}=\sqrt{\frac{\mathrm{T}_{1}}{\mathrm{T}_{2}}}\)
⇒ \(\frac{1}{4}=\frac{27+273}{\mathrm{T}_{2}}\)
⇒ T₂ = 300 × 4 = 1200 K
⇒ T₂ = 1200 – 273 = 927° C.

Question 6.
Sound waves from a point source are propagating in all directions. What will be the ratios of amplitude at a distance 9 m and 25 m from the source?
(a) 9 : 25
(b) 25 : 9
(c) 3 : 5
(d) 81 : 625
Answer:
(b) 25 : 9

II. Fill in the blanks:

Question 1.
Sound waves in a gas are ______.
Answer:
Longitudinal.

Question 2.
The velocity of sound is the largest in ______.
Answer:
Steel.

Question 3.
Hertz is the unit of ______.
Answer:
Frequency.

Question 4.
Sound travels in rocks in the form of ______.
Answer:
Both longitudinal and transverse elastic waves.

Question 5.
The velocity of sound varies directly as the square root of the ______.
Answer:
The absolute temperature of the gas.

Question 6.
Reflection of sound waves obey the ______.
Answer:
Laws of reflection.

Question 7.
RADAR is the short form of ______.
Answer:
Radio Detection and Ranging.

Question 8.
The abbreviation of SONAR is ______.
Answer:
Sound Navigation and Ranging.

III. Match the following

Question 1.

Medium	Speed of Sound (m/s)
(i) Copper	(a) 343
(ii) Water	(b) 331
(iii) Air (0° c)	(c) 5010
(iv) Air (at 20° c)	(d) 1493

Answer:
(i) (c) 5010
(ii) (d) 1493
(iii) (b) 331
(iv) (a) 343.

Question 2.

Waves	Range
(i) Audible	(a) 340 m/s
(ii) Sound	(b) greater than 20kHz
(iii) Infrasonic	(c) 20Hz – 20 kHz
(iv) Light	(d) below 20 Hz
(v) Ultrasonic	(e) 3 × 108 m/s

Answer:
(i) (c) 20 Hz – 20 kHz
(ii) (a) 340 m/s
(iii) (d) below 20 Hz
(iv) (e) 3 × 10⁸ m/s
(v) (b) greater than 20 kHz.

IV. Assertion and Reason Questions

Question 1.
Assertion: Sound wave cannot propagate through a vacuum but light can.
Reason: Sound wave cannot be polarised but light can.
(a) Both assertion and reason are true and the reason is the correct explanation of the assertion.
(b) Both assertion and reason are true but the reason is not the correct explanation of the assertion.
(c) Assertion is true but the reason is false.
(d) Both assertion and reason are false.
Answer:
(b) Both assertion and reason are true but the reason is not the correct explanation of the assertion.
Explanation: Sound waves, being mechanical waves, cannot travel through a vacuum. Light waves, electromagnetic waves, can travel through a vacuum.

Question 2.
Assertion: The velocity of sound increases with increase in humidity.
Reason: Velocity of sound does not depend upon the medium.
(a) both assertion and reason are true and the reason is the correct explanation of the assertion.
(b) both assertion and reason are true but reason is not the correct explanation of the assertion.
(c) Assertion is true but reason is false.
(d) Assertion is false but the reason is true.
Answer:
(c) The assertion is true but the reason is false.
Explanation: Velocity of sound increases with increase in humidity. The velocity of sound depends upon medium.

V. Answer Very Briefly

Question 1.
What is sound? Is it a force or energy?
Answer:
Sound is a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid. Sound is not a force, it is an energy.

Question 2.
In which type of media, can longitudinal waves be propagated?
Answer:
Longitudinal waves can be propagated through solids, liquids and gases.

Question 3.
How does sound reach our ears from various sources?
Answer:
Sound reaches our ears in the form of transverse waves or vibrations from its source of production.

Question 4.
What is the minimum distance between two points in a wave having a phase difference of 2π?
Answer:
The minimum distance is the wavelength.

Question 5.
Suppose you and your friend are on the Moon. Will you be able to hear any sound produced by your friend?
Answer:

• As the Moon does not have air, you will not be able to hear any sound produced by your friend.
• Hence, you understand that the sound produced due to the vibration of different bodies needs a material medium like air, water, steel, etc, for its propagation.
• Hence, sound can propagate through a gaseous medium or a liquid medium or a solid medium.

Question 6.
What is the effect of pressure on the speed of sound in gas?
Answer:
The increase of pressure has no effect on the speed of sound in a gas.

Question 7.
Write down the difference between the sound and light waves.
Answer:

Sound	Light
1. Medium is required for the propagation	1. Medium is not required for the propagation.
2. Sound waves are longitudinal.	2. Light waves are transverse.
3. Wavelength ranges from 1.65 cm to 1.65 m.	3. Wavelength ranges from 4 × 10-7 m to 7 × 10-7 m.
4. Sound waves travel in the air with a speed of about 340 ms-1 at NTP.	4. Light waves travel in the air with a speed of 3 × 108 ms-1

Question 8.
Define particle velocity.
Answer:
The velocity with which the particles of the medium vibrate in order to transfer the energy in the form of a wave is called particle velocity.

Question 9.
Define wave velocity.
Answer:
The velocity with which the wave travels through the medium is called wave velocity.

Question 10.
Define velocity of a sound wave.
Answer:
The distance travelled by a sound wave in unit time is called the velocity of a sound wave.
\(\text { Velocity }=\frac{\text { Distance }}{\text { Time taken }}\)

Question 11.
State the laws of reflection of sound.
Answer:
The incident wave, the normal to the reflecting surface and the reflected wave at the point of incidence lie in the same plane.
The angle of incidence ∠i is equal to the angle of reflection ∠r.

Question 12.
State ‘Laws of reflection’.
Answer:

• The incident wave, the normal to the reflecting surface and the reflected wave at the point of incidence lie in the same plane.
• The angle of incidence ∠i is equal to the angle of reflection ∠r.

Question 13.
What is meant by rarer and denser medium?
Answer:

1. Rarer medium: The medium in which the velocity of sound increases compared to other medium is called rarer medium. (Water is rarer compared to air for sound).
2. Denser medium: The medium in which the velocity of sound decreases compared to other medium is called denser medium. (Air is denser compared to water for sound)

VI. Problem Corner

Question 1.
A wave of length 0.60 cm is produced in air and travels with a velocity of 340 ms^-1. Will it be audible to the human ear?
Solution:
Wavelength, λ = 0.6 × 10^-2 m
Velocity of sound, v = 340 ms^-1
Frequency, n = \(\frac{v}{\lambda}\)
⇒ n = \(\frac{340}{0.6 \times 10^{-2}}\)
⇒ n = 566.66 × 10²
⇒ n = 567 × 10² Hz.

Question 2.
Consider a source moving towards a listener at a speed of 0.9 v. Where v is the velocity of sound. Calculate the apparent frequency if the actual frequency is 600 Hz.
Solution:

Question 3.
Audible frequencies have a range of 20 Hz to 20,000 Hz. Express it in terms of wavelength in air.
Answer:
Let the velocity of sound in air be 340 m/s
Initial frequency v₁ = 20 Hz
Initial wavelength λ₁ = \(\frac{v}{V_1}\)
= \(\frac{340}{20}\) = 17 m
Final frequency v₂ = 20 × 10³ Hz
Final wavelength λ₂ = \(\frac{340}{20×10³}\)
= 17 × 10^-3 = 0.017 m
The range of wavelength is from 17 m to 0.017 m

VII. Answer in detail.

Question 1.
Write down the applications of echo?
Answer:
Applications of echo:

• Some animals communicate with each other over long distances and also locate objects by sending the sound signals and receiving the echo as reflected from the targets.
• The principle of echo is used in obstetric ultrasonography, which is used to create real – time visual images of the developing embryo or fetus in the mother’s uterus. This is a safe testing tool, as it does not use any harmful radiations.
• Echo is used to determine the velocity of sound waves in any medium.

Question 2.
Classify sound waves based on their frequencies.
Answer:
(i) Audible waves : These are sound waves with a frequency ranging between 20 Hz and 20,000 Hz. These are generated by vibrating bodies such as vocal cords, stretched strings etc.

(ii) Infrasonic waves : These are sound waves with a frequency below 20 Hz that cannot be heard by the human ear. eg: waves produced during earth quake, ocean waves, sound produced by whales, etc.

(iii) Ultrasonic waves : These are sound waves with a frequency greater than 20 kHz, Human ear cannot detect these waves, but certain creatures like mosquito, dogs, bats, dolphins can detect these waves, eg: waves produced by bats.

Question 3.
Write down the concept of Ear trumpet and Megaphone.
Answer:
Ear trumpet:

• Ear trumpet is a hearing aid, which is useful by people who have difficulty in hearing.
• In this device, one end is wide and the other end is narrow. The sound from the sources fall into the wide end and are reflected by its walls into the narrow part of the device. This helps in concentrating the sound and the sound enters the eardrum with more intensity. This enables a person to hear the sound better.

Megaphone:

• A megaphone is a horn – shaped device used to address a small gathering of people.
• It’s one end is wide and the other end is narrow. When a person speaks at the narrow end, the sound of his speech is concentrated by the multiple reflections from the walls of the tube. Thus, his voice can be heard loudly over a long distance.

Question 4.
What is the Doppler effect? Derive the formula for the change in apparent frequency
1. Both source and listener move towards and away from each other.
2. Both source and listener move one behind the other source follows the listener and listener follows the source.
3. A source at rest, listener moves towards and away from the source.
4. A listener at rest, the source moves towards and away from the listener.
Answer:
1.

Position of source and listener	Note	Expression for apparent frequency
(i) Both source and listener move (ii) They move towards each other	(a) Distance between source and listener decreases. (b) Apparent frequency is more than actual frequency.	\(n^{\prime}=\left(\frac{v+v_{\mathrm{L}}}{v-v_{\mathrm{S}}}\right) n\)
(i) Both source and listener move (ii) They move away from each other	(a) Distance between source and listener increases. (b) Apparent frequency is less than actual frequency. (c) vS and vL become opposite to that in case-1.	\(n^{\prime}=\left(\frac{v-v_{\mathrm{L}}}{v+v_{\mathrm{S}}}\right) n\)

2.

Position of source and listener	Note	Expression for apparent frequency
(i) Both source and listener move (ii) They move one behind the other (iii) Source follows the listener	(a) Apparent frequency depends on the velocities of the source and the listener. (b) vS becomes opposite to that in case-2.	\(n^{\prime}=\left(\frac{v-v_{\mathrm{L}}}{v-v_{\mathrm{S}}}\right) n\)
(i) Both source and listener move (ii) They move one behind the other (iii) The listener follows the source	(a) Apparent frequency depends on the velocities of the source and the listener. (b) vS and vL become opposite to that in case-3.	\(n^{\prime}=\left(\frac{v+v_{\mathrm{L}}}{v+v_{\mathrm{s}}}\right) n\)

3.

Position of source and listener	Note	Expression for apparent frequency
(i) Source at rest (ii) Listener moves towards the source	(a) Distance between source and listener decreases. (b) Apparent frequency is more than actual frequency. (c) vS = 0 in case-1.	\(n^{\prime}=\left(\frac{v+v_{\mathrm{L}}}{v}\right) n\)
(i) Source at rest (ii) Listener moves away from the source	(a) Distance between source and listener increases. (b) Apparent frequency is less than actual frequency. (c) vS = 0 in case-2.	\(n^{\prime}=\left(\frac{v-v_{\mathrm{L}}}{v}\right) n\)

4.

Position of source and listener	Note	Expression for apparent frequency
(i) Listener at rest (ii) Source moves towards the listener	(a) Distance between source and listener decreases. (b) Apparent frequency is more than actual frequency. (c) vL = 0 in case-1.	\(n^{\prime}=\left(\frac{v}{v-v_{\mathrm{S}}}\right) n\)
(i) Listener at rest (ii) Source moves away from the listener	(a) Distance between source and listener increases. (b) Apparent frequency is less than actual frequency. (c) vL = 0 in case-2.	\(n^{\prime}=\left(\frac{v}{v+v_{\mathrm{S}}}\right) n\)

Question 5.
Explain echo method to measure velocity’ of sound.
Answer:
Apparatus required: A source of sound pulses, a measuring tape, a sound receiver, and a stop watch.
Procedure:

1. Measure the distance ‘d’ between the source of sound pulse and the reflecting surface using the measuring tape.
2. The receiver is also placed adjacent to the source. A sound pulse is emitted by the source.
3. The stopwatch is used to note the time interval between the instant at which the sound pulse is sent and the instant at which the echo is received by the receiver. Note the time interval as ‘t’.
4. Repeat the experiment for three or four times. The average time taken for the given number of pulses is calculated.

Calculation of speed of sound : The sound pulse emitted by the source travels a total distance of 2d while travelling from the source to the wall and then back to the receiver. The time taken for this has been observed to be ‘t’. Hence, the speed of sound wave is given by:
Speed of sound = \(\frac{distence Travelled}{Time Taken}\)
= \(\frac{2d}{t}\)

You can Download Samacheer Kalvi 9th Social Science Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Samacheer Kalvi 9th Social Science Economics Solutions Chapter 4 Tamilnadu Agriculture

Tamilnadu Agriculture Textual Exercise

I. Choose the correct answer:

Question 1.
Irrigated land surface out of cultivable land is
(a) 27%
(b) 57%
(c) 28%
(d) 49%
Answer:
(b) 57%

Question 2.
Out of the following which is not a food crop?
(a) Bajra
(b) Ragi
(c) Maize
(d) Coconut
Answer:
(d) Coconut

Question 3.
The productivity of paddy during the year 2014-2015
(a) 3,039 kg
(b) 4,429 kg
(c) 2,775 kg
(d) 3,519 kg
Answer:
(b) 4429 kilogram

Question 4.
Both agricultural productivity and food productivity has ……..
(a) decreased
(b) not stable
(c) remained stable
(d) increased
Answer:
(d) Increased

Question 5.
The North-East monsoon period in Tamilnadu ………
(a) August – October
(b) September – November
(c) October – December
(d) November – January
Answer:
(c) October – December

II. Fill in the blanks.

1. The major occupation of people in Tamilnadu is ……..
2. Tamilnadu receives rainfall from the ……. monsoon.
3. The total geographical area of Tamil Nadu is …….. hectares.

Answers:

1. Agriculture
2. Northeast
3. 30 lakh and 33 thousand

III. Match the following:

Answers:
1. (e)
2. (d)
3. (c)
4. (b)
5. (a)

IV. Give short Answers

Question 1.
Give two examples for each food crop and non-food crops.
Answer:

1. Food crops: Paddy, Wheat.
2. Non-food crops: Coconut, Cotton.

Question 2.
What are the factors responsible for the changes in the cropping area?
Answer:
The size of the total cropping land in Tamil Nadu is 4,544 thousand hectares and this keeps on changing every year. Sufficient rains at the proper period will increase this extent of land. Failure or shortage in rainfall leads to the reduction of land usage for cultivation. .

Question 3.
Who monitors the quantity and quality of groundwater?
Answer:
The Union Water Board is constantly monitoring the level and nature of groundwater.

Question 4.
Tabulate the productivity of paddy from 1965 to 2015.
Answer:

Question 5.
On what factors does crop cultivation depend? List out the factors on which crop cultivation depends.
Answer:
Crop cultivation depends on – rainfall, availability of water, weather and market prices.

Question 6.
Differentiate small and marginal farmers.
Answer:

Small Farmers	Marginal Farmers
Small farmers cultivate in lands ranging from 1 -2 hectares.	Marginal farmers cultivate in lands within 1 hectare.

V. Answer in Detail

Question 1.
Give a note on water resources in Tamilnadu.
Answer:

1. There are no perennial rivers in Tamil Nadu.
2. Tamil Nadu receives the required water from the northeast and southwest monsoons.
3. When the southwest monsoon rains are high in the catchment areas of Kavery River in Karnataka, Dams there get filled and in turn, Kavery River in Tamil Nadu gets water.
4. The area under irrigation is about 57% of the total area under cultivation.
5. Canals, lakes, open wells and bore wells also provide water for irrigation.
6. But agriculture in Tamil Nadu is dependent on groundwater.

Question 2.
What are the problems faced by using groundwater for agriculture?
Answer:
Agriculture in Tamil Nadu is dependent mostly on groundwater. Use of groundwater for agriculture creates many hardships too. There would be no suffering if the amount of water taken from the underground and the amount of water that goes into the underground during the rainy season are equal. On the contrary, as the amount of water taken increases, the ground water goes down resulting in complete dryness or change into unusable water.

Question 3.
Discuss the source of irrigation for agriculture.
Answer:

1. The northeast monsoon (oct-Dec) is a major source of water for Tamil Nadu.
2. The Northeast monsoon rains are stored in reservoirs, lakes, and tarns for cultivation.
3. Conventional water bodies like lakes, ponds, and canals provide water for agriculture in Tamil Nadu.
4. 2239 canals mn through Tamil Nadu covering a length of 9750 km.
5. There are 7985 small lakes, 33,142 large lakes, 15 lakh open wells.
6. There are 3,54,000 borewells in the state where agriculture is carried out with the help of these water resources.
7. The area of land that is irrigated from the lakes is very low. Nearly 3.68 lakh hectares of land obtain water from lakes.
8. The canals provide water to 6.68 lakh hectares.
9. Borewells irrigate 4.93 lakh hectares and open wells provide water to 11.91 lakh hectares of land.
10. Still in Tamil Nadu agriculture is dependent on groundwater.

Question 4.
Tabulate the crops grown in Tamil Nadu.
Answer:
Crops grown in Tamil Nadu are:

1. Paddy
2. Black gram
3. Maize
4. Coconut
5. Corn
6. Sugarcane
7. Millets

VI Activity

Question 1.
Analyse the cultivation of food crops and non-food crops of your village/area.
Answer:

Question 2.
Thanjavur is famous for which crop? Why is it so? Research.
Answer:
(a) The Principal crops in Thanjavur District are paddy, green gram, black gram, sugarcane,
cotton, groundnut, gingelly, coconut, fruits and vegetables in the areas where irrigation facility is available.
In the rainfed area cholam, kumbu, ragi, maize, some edible oil seeds, non-edible oilseeds, fodder crops etc.
(b) The land is ideal for growing crops like Rice. The major portion of Thanjavur land consists of alluvial deposits. Thanjavur is known as the Rice bowl of Tamil Nadu.
(c) Soil and Water Management Research Institute Kalluthottam was established in 1972. They conduct research on the improved methods of water conveyance, application, and utilization on rice and other crops grown in the Cauvery Delta zone.

Question 3.
Collect statistical data, where paddy is being cultivated at Thanjavur District, which is called the Nerkalanjium of Tamil Nadu.
Answer:
(a) Thanjavur is known as the Rice bowl of Tamil Nadu.
(b) Samba cultivation has picked up in Thanjavur District.
(c) In Tiruvarur district direct sowing has been done on 70,000 hectares of land, while transplantation has been completed on 11,500 hectares.
(d) High concentrations of rice production is found in the taluks of Orathanadu, Thiruvaiyaru, Kumbakonam, Pabanasam, Thiruvidaimarudur, etc.

Tamilnadu Agriculture Additional Questions

I. Choose the correct answer.

Question 1.
This is the total employee population engaged in agriculture according to the 2001 census.
(a) 48.3%
(b) 49.3%
(c) 47.3%
(d) 46.3%
Answer:
(b) 49.3%

Question 2.
The total geographical area of Tamil Nadu is
(a) one crore thirty lakh and thirty-three thousand hectares
(b) one crore twenty lakh and thirty-two thousand hectares
(c) one crore forty lakh and thirty-three thousand hectares
(d) one crore twenty-five lakh and thirty thousand hectares
Answer:
(a) one crore thirty lakh and thirty-three thousand hectares

Question 3.
The number of blocks identified as excessive users of groundwater are
(a) 140
(b) 141
(c) 139
(d) 138
Answer:
(c) 139

Question 4.
……… cultivation is carried out at a large scale of 30 percent cultivated land area.
(a) Paddy
(b) Varagu
(c) Cholam
(d) Kambu
Answer:
(a) Paddy

Question 5.
Production capacity of rice in Tamil Nadu was …….. Kg per hectare in 2014 – 2015.
(a) 4420
(b) 4422
(c) 4425
(d) 4427
Answer:
(d) 4427

II. Fill in the blanks.

1. The agricultural workers in Tamil Nadu in 2011 were ……..
2. A major portion of the workers involved in agricultural activities are ……… labourers.
3. Most of the cultivators in Tamil Nadu are …….. farmers.
4. There are no …….. rivers in Tamil Nadu.
5. The ……… Board is constantly monitoring the level and nature of groundwater.
6. Tamil Nadu agriculture is dependent on ……….
7. Crops are divided into ……. and ……….

Answers:

1. 96 lakhs
2. landless
3. marginal
4. Perennial
5. Union Ground Water
6. groundwater
7. food, non-food

III. Match the following:

Answers:
1. (d)
2. (a)
3. (b)
4. (c)

IV. Give Short Answers.

Question 1.
What happened to the number of workers engaged in Agriculture in the past ten years?
Answer:
It has been noticed that the number of farmers in Tamilnadu has got reduced during the last 10 years according to the 2011 census data. Similarly, the number of agricultural workers also reduced during the same period.

Question 2.
What type of employees are involved in agricultural activities?
Answer:
A major portion of the workers involved in agricultural activities are landless labourers. All the landholders do not have the same amount of land. Many have very little land and very few people hold large areas of land.

Question 3.
“The total area of land under agriculture is shrinking fast.” What does it show?
Answer:
The total land area under agriculture is shrinking fast not only in Tamilnadu but also throughout India. The number of marginal farmers has increased in India. In contrast, the number of marginal farmers is decreasing in Tamil Nadu. This shows that the farmers are doing other occupations.

Question 4.
Comment on water resources of Tamil Nadu.
Answer:
There are no perennial rivers in Tamil Nadu. Tamil Nadu receives the required water from the Northeast and Southwest monsoons. When the southwest monsoon rains are high in the catchment areas of the Cauvery River in Karnataka dams get filled and in turn, the Cauvery river in Tamil Nadu gets water.

Question 5.
How is the productivity of crops?
Answer:
The productivity of crops continues to increase. For example, the productivity of paddy in 1965 – 66 was 1,409 kg. It increased to 2,029 kg in 1975-76 and 2,372 kg in 1985-86. It . increased to 2,712 kg after a decade. The production was 4,429 kg in the year 2014-15. In the past fifty years, the productivity of paddy has increased more than three times.

V. Answer in Detail.

Question 1.
Explain irrigation and crop types.
Answer:
All cultivated crops can be classified as food crops and non-food crops. 57 percentage of the total land under food grain cultivation is irrigated. In 2014-15, 59 percentage of food crops and 50 percentage of nonfood crops were irrigated in Tamilnadu.

The total area of land cultivated in Tamil Nadu was 59 lakh and 94 thousand hectares in 2014—2015. Out of this non-food crops were 76%.

Paddy cultivation is carried out at a large scale of 30 percent cultivated land area and other food crops in 12 percent area. Millets are cultivated in a very low percentage of area. Sorghum(Cholam) cultivation in 7 percent land area, cumbu in one percent and ragi in 1.7 percent. Other millets occupy 6 percent in the year 2014-2015.

The area cultivatable land changes every year as a result of many factors such as rainfall, availability of water, weather and market prices.

You can Download Samacheer Kalvi 10th Social Science Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 10th Social Science Geography Solutions Chapter 7 Human Geography of Tamil Nadu

Human Geography of Tamil Nadu Textual Exercise

I. Choose the correct answer.

Question 1.
The delta which is known as Granary of South India is ……………….
(a) Cauvery delta
(b) Mahanadi delta
(c) Godavari delta
(d) Krishna delta
Answer:
(a) Cauvery delta

Question 2.
Second staple food of the people of Tamil Nadu is:
(a) Pulses
(b) Millets
(c) Oilseeds
(d) Rice
Answer:
(b) Millets

Question 3.
Literacy rate of Tamil Nadu as per 2011 census is ……………
(a) 80.32%
(b) 62.33%
(c) 73.45%
(d) 80.33%
Answer:
(d) 80.33%

Question 4.
A major hydro-electric power project of Tamil Nadu is:
(a) Mettur
(b) Papanasam
(c) Sathanur
(d) Tungabhadra
Answer:
(a) Mettur

Question 5.
Number of major and minor ports in Tamil Nadu are
(a) 3 and 15
(b) 4 and 15
(c) 3 and 16
(d) 4 and 16
Answer:
(a) 3 and 15

II. Fill in the blanks.

1. Agriculture of Tamil Nadu constitutes …………….. % of its economy.
2. Sathanur dam is constructed across the river …………..
3. Tamil Nadu ranks …………….. in India with a share of over 20% in total road projects under operation in the Public – Private Partnership (PPP).
4. ………….. is the third largest airport in India after Mumbai and Delhi.
5. The difference between the value of exports and imports is called ………….
Answers:
1. 21
2. Thenpennai
3. Second
4. Chennai International Airport
5. Balance of trade

III. Match the following.

Answer:
1. (b)
2. (d)
3. (a)
4. (c)

IV. Questions 1-2 are assertion and reasoning type

Question 1.
Assertion (A): Coimbatore, Tiruppur and Erode region is called as The Textile Valley of Tamil Nadu.
Reasoning (R): They contribute a major share to the state’s economy through textiles.
(a) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R) are true but, (R) does not explain (A)
(c) (A) is true but (R) is false
(d) (A) is false but (R) is true
Answer:
(a) Both (A) and (R) are true and (R) explains (A)

Question 2.
Assertion (A): The Nilgiris is the least populated district of Tamil Nadu
Reasoning (R): It is located in the western most part of Tamil Nadu.
(а) Both (A) and (R) are true and (R) explains (A)
(b) Both (A) and (R) are true but, (R) does not explain (A)
(c) (A) is true but (R) is false
(d) (A) is false but (R) is false
Answer:
(b) Both (A) and (R) are true but, (R) does not explain (A)

V. Answer the following in briefly.

Question 1.
Explain the cropping seasons of Tamil Nadu.
Answer:

Question 2.
Why is Coimbatore called the Manchester of Tamil Nadu?
Answer:
Coimbatore has the ideal conditions for cotton cultivation – Humid weather in the early stages and hot weather during the harvest period. Cotton cultivation and the textile industries are the reasons to call Coimbatore as the “Manchester of Tamil Nadu”.

Question 3.
Name the important multipurpose projects of Tamil Nadu.
Answer:
Mettur Dam, Amaravathi Dam, Papanasam Dam, Bhavani Sagar Dam.

Question 4.
What is MRTS?
Answer:

1. Mass Rapid Transport System (MRTS) a well established suburban railway network. Currently developing a Metro system, with its first underground operation since May 2017.
2. It is mainly started to manage the crowd during peak hours. The elevated metro system. Connects the heart of the city from North to South.

Question 5.
List out the air ports and sea ports of Tamil Nadu.
Answer:
Airports:

1. Chennai International Airport
2. Coimbatore International Airport
3. Madurai International Airport
4. Tiruchirapalli International Airport

Domestic Airports:

1. Tuticorin and Salem

Sea Port: Major Sea Ports are:

1. Chennai
2. Ennore and
3. Tuticorin
   Intermediate port at Nagapattinam and 15 minor ports.

Question 6.
Have you heard about any stampede in your district? write about that incident briefly.
Answer:
During Athivaradhar festival minor stampede that brokeout on Thursday (18^th July 2019) the crowd flocked to Kancheepuram as it was an auspicious day after the lunar eclipse. Four people died.

On 21^st April 2019 atleast seven people died in stampede in Tamil Nadu during a temple festival at Muthuaiyampalayam Karuppusamy temple in Thuraiyur a village near Trichy (Sunday).

VI. Distinguish between the following.

Question 1.
Marine Fishing and Inland fishing
Answer:

Marine Fishing	Inland Fishing
It is carried out in oceans and seas.	Inland fishing is carried out in lakes, rivers, ponds, estuaries, backwaters and swamps.
Large mechanised boats are used for fishing.	Catamaran, diesel boats and floating nets are used in fishing.
The fish varieties caught are sharks, flying fish, counch, catfish, silver bellies and crabs.	Oysters and prawns are cultured in original nurseries.
Chennai, KanyaKumari, Tirunelveli, Nagapattinam, Thanjavur and Ramanathapuram.	Vellore, Cuddalore, Sivagangai and Virudhunagar districts are inland fish production of the state.

Question 2.
Food Crops and Non- Food Crops
Answer:

Food Crops	Non- Food Crops
Food crops are mainly grown for consumption	They are mainly grown for sale purpose
Paddy is the main food crop and cereals, pulses and millets are also the second staple food of the people of Tamil Nadu	Sugarcane, cotton, tree and coffee
Cauvery delta is known as the Granary of South India leading in rice cultivation	Tiruvallur, Kancheepuram, Vellore, coimbatore, Cuddalore, Erode, Madurai, Ramanatha Puram, Salem, Thoothukudi, Nilgiris and yercaud.

Question 3.
Surface Water and Ground Water
Answer:

Surface Water	Ground Water
The total surface water potential of the state is about 24,864 mem.	The utilizable groundwater resource of the state is 22,423 mem.
There are 17 major river basins in the state with 81 reservoirs and about 41,262 tanks	The current level of utilization of water is about 13,558 mem.
Most of the surface water has already been tapped, primarily for irrigation, where water use in the largest.	60% of the available recharge, while about (8875 mcm) 40% is the balance available for use.

VII. Give reasons for the following

Question 1.
Farmers switch over from inorganic to organic farming.
Answer:
By continuous usage of chemical fertilizers, pesticides and insecticides the soil became unfit for cultivation after some years. It causes a threat to agriculture. So to bring back the soil to fertility and to make it fit for cultivation farmers switch over from inorganic to organic farming. Organic wastes, biological pest control crop residues and animal manure only used under organic farming.

Question 2.
Cities are densely populated than the villages.
Answer:
Agriculture, job opportunities and industrial development are the main causes of population density in the cities then the villages.

Question 3.
Karur is Called the Textile Capital of Tamil Nadu.
Answer:
Karur is an industry town and is very famous for cottage and hand-loom textile industries. Moreover state’s most of the textile goods exports is from Karur district. That is why Karur is called the textile capital of Tamil Nadu.

Question 4.
Mostly stampede occurs in Temples.
Answer:
Most of the religious festivals are located in areas like banks of rivers hilly terrains or mountain tops. These areas lack proper pathways, posing a geographical risk to the pilgrims. It often disrupts the orderly movement of crowds resulting in irrational and dangerous movement for self-protection, leading to injuries and fatalities. Because of the lack of physical infrastructure, the mob behaviour increases the sense of threat, which results in a stampede.

VIII. Answer the following in a paragraph.

Question 1.
Write about the plantation farming of Tamil Nadu.
Answer:
Plantation Crops: Tea, coffee, cashew, rubber, pepper and cinchona.

The hill slopes with laterite soil and acidic-nature is ideal for the plantation crops.

Tea: Tea plantations are found in the hills of the Nilgins and Coimbatore. Notable region for tea estates Nilgiris.

Coffee: Coffee plants are grown in the hills of Western Ghats as well as Eastern Ghats. It is also found in the hilly slopes of Dindigui, Madurai, Theni and Salem districts.
Notable places: Yercaud, Kolli hills and Kodaikanal,

Rubber: Rubber plantations are significant in Kanyakumari.

Cashew: It is extensively cultivated in Cuddalore district.

Pepper: Confined to the warm and wet slopes of Eastern and Western Ghats of Tamil Nadu.

Cinchona: It is planted at heights varying from 1060 to 1280 metres in Anaimalai hills.

Cardamom: Cardamom estates are located at few places in the hills of Madurai region at an elevation of 915 to 1525 metres.

Position: Tamil Nadu stands second in area and production of tea and coffee next to Assam and Karnataka respectively.

Question 2.
Give an account on water resources of Tamil Nadu.
Answer:

1. Tamil Nadu constitutes 4% of India’s land area and is inhabited by 6% of India’s population, but has-only 2.5% of India’s water resources.
2. More than 95% of the surface water and 80% of the ground water have already been put into use.
3. Major uses of water include human/animal consumption irrigation and industrial use.
4. The state is heavily dependent on monsoon rains.
5. The annual average rainfall is around 930 mm (47% during the northeast monsoon, 35% during the south west monsoon, 14% in summer and 4% in winter.
   

Question 3.
Bring out the mineral distribution in Tamil Nadu.
Answer:
(i) Tamil Nadu is the leading holder of country’s resources of vermiculite, magnetite, dunite, rutile, garnet, molybdenum and ilmenite.

(ii) The state accounts for the country’s 55.3% of lignite, 75% of vermiculite, 69% of dunite, 59% of garnet, 52% of molybdenum and 30% of titanium mineral resources.
Important minerals are found in the state are as follows:

1. Neyveli has large lignite resources.
2. Coal is available in Ramanathapuram
3. Oil gas are found in the Cauvery basin
4. Iron deposits are found in Kanjamalai region in Salem district and Kalrayan Malai region of Tiruvannamalai district.
5. Magnesite ores are available near Salem.
6. Bauxite is found in Servarayan Hills, Kotagiri, Udagamandalam, Palani and Kollimalai areas.
7. Gypsum is obtained in Tiruchirappalli, Tirunelveli, Thoothukudi and Virudhunagar districts.
8. Ilmenite and rutile are found in the sands of Kanyakumari beach.
9. Limestone is available in Coimbatore, Cuddalore, Dindigul, Kancheepuram, Karur, Madurai, Nagapattinam, Namakkal, Perambalur, Ramanathapuram, Salem and Tiruvallur districts.
10. Magnesite is obtained in Coimbatore, Dharmapuri, Karur, Namakkal, the Nilgiris, Salem.
11. Feldspar, quartz, copper and lead are found in some parts of the state.

Question 4.
State the densely populated regions of Tamil Nadu and account for its high density.
Answer:

1. The number of persons living per square km is referred as population density.
2. A place is said to have high density of population if number of persons living per sq km is above 800.
3. As per 2011 census the density of population in Tamil Nadu is 555 per sq.km

Densely populated regions of Tamil Nadu:
Chennai is the densest district – 26,903 persons per sq.km followed by Kanyakumari (1106), Tiruvallur (1049), Kancheepuram (927), Madurai (823), Coimbatore (748), Cuddalore (1702), Thanjavur (691), Nagapattinam (668-), Salem (663), Vellore (646), Tiruchirappalli (602).

Question 5.
Explain the different modes of transport available in Tamil Nadu.
Answer:
Roadways:
The State has a total road length of 167,000 km, In which 60,628km are maintained by state Highways Department. It ranks second in India with a share of over 20% in total road projects under operation in the Public-Private Partnership (PPP) model.

Railways:

• Tamil Nadu has a well-developed rail network as part of Southern Railway, headquartered at Chennai.
  The present Southern Railway network extends over a large area of India’s southern peninsula, covering Tamil Nadu, Kerala, Puducherry, minor portions of Karnataka and Andhra Pradesh.
• Tamil Nadu has a total railway track length of 6,693 km with 690 railway stations in the state.
• The system connects it with most of the major cities in India.
• Main rail junctions in the state include Chennai, Coimbatore, Erode, Madurai, Salem, Tiruchirappalli and Tirunelveli.
• Chennai has a well-established suburban railway network, a Mass Rapid Transport System (MRTS) and is currently developing a Metro system, with its first underground stretch in operation since May 2017.

Airways:

• Tamil Nadu has four major international airports. Chennai International Airport is currently the third largest airport in India after Mumbai and Delhi.

Water ways:

• Tamil Nadu has 3 major ports. They are Chennai, Ennore and Tuticorin. It has an intermediate port at Nagapattinam and 15 minor ports. Ennore intermediate port was recently converted as a major port and handles the major coal and ore traffics in Tamil Nadu.

Question 6.
Write about Road safety rules.
Answer:
In recent years the number of road accidents in Tamil Nadu has been increasing. It is reported that 15% of the road accidents of the country takes place in Tamil Nadu.

Basic road safety rules:

1. Aware of the road signals
2. Stop, look and cross
3. Listen and ensure whether a vehicle is approaching
4. Don’t rush on roads
5. Crossroads in pedestrian crossings
6. Don’t stretch hands while driving vehicles.
7. Never crossroad at bends and stay safe in a moving vehicle.
8. Avoid speeding, Drunk and driving, use helmets and seat belts and follow traffic rules.

“Know – Risk! No – risk!”

IX. Map Study

Question 1.
Mark the areas of major crops, minerals, dams, airport and seaports.
Answer:

Human Geography of Tamil Nadu Additional Questions

I. Choose the correct answer.

Question 1.
Tea, Coffee, rubber, pepper and cashew are …………. crops.
(a) Food
(b) Fiber
(c) Plantation
Answer:
(c) Plantation

Question 2.
The word Agriculture is derived from the ……………….. words “ager and Cultura”.
(a) Latin
(b) Greek
(c) Tamil
(d) Spanish
Answer:
(a) Latin

Question 3.
Rice, Cotton, Sugercane are grown with …………….
(a) Drying farming
(b) Irrigation farming
(c) Cattle reasing
Answer:
(b) Irrigation farming

Question 4.
In Tamil Nadu Rice Research Institute is situated at:
(a) Aduthurai
(b) Madurai
(c) Thiruvallur
(d) Chennai
Answer:
(a) Aduthurai

Question 5.
Millets are ……………… crops.
(a) Wet crops
(b) Dry crops
(c) Plantation
Answer:
(b) Dry crops

Question 6.
To promote ……………….. a central scheme named ‘National Project on Organic Farming’was launched.
(a) mixed farming
(b) organic farming
(c) aquaculture
(d) plantation farming
Answer:
(b) organic farming

Question 7.
Which is known as the Textile capital of Tamil Nadu?
(a) Salem
(b) Karur
(c) Tirunelveli
Answer:
(b) Karur

Question 8.
……………….. is also known as ‘poor man’s cow’.
(a) Goat
(b) Sheep
(c) Buffalo
(d) Horse
Answer:
(a) Goat

Question 9.
The most populated district in Tamil Nadu is …………….
(a) Madurai
(b) Tiruvallur
(c) Chennai
Answer:
(c) Chennai

Question 10.
districts lead in the Inland fish production.
(a) Chennai
(b) Cuddalore
(c) Sivagangai
(d) Vellore
Answer:
(d) Vellore

II. Fill in the blanks:

1. …………. irrigation is most predominant irrigation system in TamilNadu.
2. ……….. Dam is one of the biggest earthen dams in the country.
3. Amaravathi reservoir is notable for the …………….
4. Papanasam dam is also known as ………….. dam.
5. Parappalar project is located near …………….
6. Tamil Nadu occupies ……………… position in the country in silk production.
7. The Vellore district is the top exporter of finished …………. in the country.
8. Tamil Nadu accounts for about ………….. of India’s …………. exports.
9. Tamil Nadu ranks among the Indian states in population density.
10. ………… in considered the ‘fire works capital’ of India.
Answers:
1. Well
2. Bhavani
3. Mugger crocodiles
4. Karaiyar
5. Ottanchatram
6. Fourth
7. leather goods
8. 17%, Software
9. 12th
10. Sivakasi

III. Match the following.

a.

1.	Rearing of birds	(a)	Apiculture
2.	Rearing of honeybees	(b)	Horticulture
3.	Rearing of silkworms	(c)	Poultry farming
4.	Growing fruits	(d)	Sericulture

Answer:
1. (c)
2. (a)
3.(d)
4.(b)

b.

1.	Wet fanning	(a)	Millets
2.	Dry farming	(b)	Rice
3.	Plantation farming	(c)	Sugarcane
4.	Market gardening	(d)	Tea, Coffee
5.	Irrigation farming	(e)	Kancheepuram

Answer:
1. (b)
2. (a)
3. (d)
4. (e)
5. (c)

IV. Answer briefly:

Question 1.
What is Agriculture?
Answer:
Agriculture is a practice of farming that includes cultivation of crops, rearing of animals, birds, forestry, fisheries and other related activities.

Question 2.
What is the Multipurpose River Valley Projects?
Answer:
Multipurpose river valley projects are basically designed for the development of irrigation for agriculture and hydropower generation they are used for many other purposes as well.

Question 3.
List out the major food crops and commercial crops of the state.
Answer:

1. The principal food crops – paddy, millets and pulses.
2. The commercial crops – sugarcane, cotton, oilseeds, spices, tea, and coffee and cashew.

Question 4.
Define Trade.
Answer:
Trade-in an exchange of goods and commodities either within the country or between countries.

Question 5.
Write a note on Tamil Nadu Rice Research Institute.
Answer:

1. Tamil Nadu Rice Research Institute was established in April 1985 under Tamil Nadu Agricultural University.
2. It is situated at AduthUrai (Thanjavur).
3. It’s function is to perform lead function for rice and rice based cropping system research with the help of existing agriculture colleges and research centers.

Question 6.
Name any four districts with low density of population.
Answer:
Nilgiris, Perambalur, Dharmapuri and Sivagangai.

Question 7.
What are minor ports?
Answer:
Minor ports are anchorage ports where cargo is transhipped from the vessel to the store.
Ex. Cuddalore, Nagapattinam, Kolachal and Rameshwaram.

Question 8.
What are the uses of Chinchona?
Answer:

• Chinchona is a forest product.
• From chinchona quinine a drug is extracted.
• Malaria is treated with this medicine.

Question 9.
Write the expansion of these abbreviated terms.

1. TNAU
2. TANTEA
3. TNPL
4. TANCEM
5. Gl
6. CLRI
7. SEZ
8. TTDC

Answer:

1. TNAU: Tamil Nadu Agriculture University
2. TANTEA: Tamil Nadu Tea Plantation Corporation Limited
3. TNPL: Tamil Nadu Newsprint and Papers Limited
4. TANCEM: Tamil Nadu Cements Corporation Limited
5. GI: Geographical Indication
6. CLRI: Central Leather Research Institute –
7. SEZ: Special Economic Zone
8. TTDC: Tamil Nadu Tourism-Development Corporation

Question 10.
Name the factors influencing agriculture.
Answer:
The factors influencing agriculture can be classified as Physical, Social and economic factors.

• Physical factors includes soil, temperature, rainfall, humidity, climate and slope of land.
• The social factors includes traditional knowledge belief and myths of farmers, farm size and holdings and fanners acceptance towards innovation.
• Economic factors are market loan assistance, government subsidy and incentives.

V. Distinguish:

Question 1.
Wet farming and Dry farming
Answer:

Wet farming	Dry farming
Water supply is available through out the year from rain fall and irrigation for farming.	Farming is carried out only during rainy season.
Rice and sugarcane are grown.	Ragi and millets are grown.

Question 2.
Commercial crops and Plantation crops
Answer:

Commercial crops	Plantation crops
Sugarcane, tobacco, oil seeds, spices, turmeric etc are commercial crops.	Tea, coffee, rubber, pepper and cashewnut are the main plantation crops.
Tobacco is yet another commercial crop grown an Dindigul, Teni and Madurai districts.	Coffee in grown in the W.Ghats and E. Ghats.

Question 3.
Imports and Exports
Answer:

Imports	Exports
Goods and services bought from overseas producers.	Goods and services sold to overseas consumers.
A country that imports goods and services loses foreign exchage currency.	A country that exports goods and services gains foreign exchange currency.
Tamil Nadu imports machineries, electrical equipments, mineral, fuel and pharmaceutical products.	Tamil Nadu exports agricultural products, Leather products, Gems, and jewellery, chemical and related products.

VI. Answer the following in detail.

Question 1.
Tourism is considered as an industry – justify. Give an account on Tourism in Tamil Nadu.
Answer:

1. Tourism is considered as an industry because of its enormous potential in creating employment for a large number of people.
2. Approximately 28 lakh foreign and 11 crore domestic tourists visit our state (Tamil Nadu) annually.
3. Reasons: The presence of ancient temples and monuments, hill stations pilgrim centres, a variety of natural land scapes, long coast line along with rich culture and heritage make Tamil Nadu the best destination for tourists.
4. Promoter: Tourism in Tamil Nadu is promoted by Tamil Nadu Tourism Development Corporation (TTDC).
5. The state currently ranks the highest among Indian states with about 25 crore arrivals (in 2013).

Question 2.
Give an account for the distribution of Textile industry in Tamil Nadu.
Answer:
Textile industry is one of the traditionally well-developed industries in Tamil Nadu. Tamil Nadu has a major share in the Indian Textile industry in terms of production and export of yams, fabrics, knitwear and garments. Tamil Nadu contributes 30% of India’s share in export of cotton, yam and fabrics.

Tropical climate availability of raw materials, demand for cotton in market, power supply from numerous power projects and abundant cheap labour are favourable factors for widespread distribution of textile industries in Tamil Nadu. The textile mills are concentrated in Coimbatore, Tirupur, Salem, Palladam, Kamr, Dindigul, Vimdhunagar, Tirunelveli, Thoothukudi, Madurai and Erode. Tamil Nadu has about 3,50,000 power looms manufacturing cotton fabrics.

Maximum units are concentrated in and around Coimbatore region for this region it is known as the “Manchester of South India”. Timpur and Erode contributes much for the state economy, therefore they are referred to as ‘Textile Valley of Tamil Nadu’.

Timpur alone contributes 70% of export of knitwear of Tamil Nadu. Erode specializes in garments and bedspreads. The city of Kamr is known as ‘Textile capital of Tamil Nadu Silk Textiles’. Tamil Nadu occupies fourth place in silk textile production in our country Kancheepuram silk is unique in its quality and is known for its traditional value all over the world. Arani, Rasipuram and Thimbuvanam are other silk centres of Tamil Nadu.

Sericulture Training Institute in Hosur training farmers to adopt agriculture along with farm work to accelerate rural industrialization Mettur, Madurai and Ramanathapuram are specialized areas for manufacturing synthetic clothes.

You can Download Samacheer Kalvi 9th Social Science Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 9th Social Science Geography Solutions Chapter 6 Man and Environment

Man and Environment Textual Exercise

I. Choose the correct answer.

Question 1.
All external influences and factors that affect the growth and development of living organisms is ………
(a) Environment
(b) Ecosystem
(c) Biotic factors
(d) Abiotic factors.
Answer:
(a) Environment

Question 2.
The ‘World Population Day’ is observed on every year.
(a) August 11^th
(b) September 11^th
(c) July 11^th
(d) January 11^th
Answer:
(c) July 11^th

Question 3.
The statistical study of human population is
(a) Demography
(b) Morphology
(c) Etymology
(d) Seismography
Answer:
(a) Demography

Question 4.
The extraction of valuable minerals and other geological minerals from the mines, is …..
(a) Fishing
(b) Lumbering
(c) Mining
(d) Agriculture
Answer:
(c) Mining

Question 5.
The Secondary sector of the economy produces …… from raw materials.
(a) Semi finished goods
(b) Finished goods
(c) Economic goods
(d) raw materials
Answer:
(b) Finished goods

Question 6.
Gradual increase of the earth’s temperature by the Green house gases in the atmosphere is called …….
(a) Acid rain
(b) thermal pollution
(c) Global warming
(d) Deforestation
Answer:
(c) Global warming

II. Consider the given statements and choose the right option given below.

Question 7.
Assertion (A): Ozone layer in the stratosphere is considered as a protective shield.
Reason (R): It prevents the UV radiation from reaching the earth’s surface.
(a) A and R are correct and A explains R
(b) A and R are correct, but A does not explain R
(c) A is incorrect but R is correct
(d) Both A and R are incorrect
Answer:
(a) A and R are correct and A explains R

Question 8.
Assertion (A): In tertiary activities, instead of producing goods by themselves, they are in the process of production.
Reason (R): People in Tertiary activities are purely eco friendly.
(a) Both A and R are incorrect
(b) A and R are correct, but A does not explain R
(c) A is correct and R is incorrect.
(d) A and R are correct and A explains R.
Answer:
(c) A is correct and R is incorrect.

III. Match the following:

Answers:
1. (c)
2. (e)
3. (d)
4. (a)
5. (b)

IV. Answer the following in brief:

Question 1.
What do you mean by the term ‘density of population’?
Answer:

1. Density of population refers to the number of people living per sq.km.
2. Population density = \(\frac { Total population }{ Total land area }\)

Question 2.
What is ‘black death’?
Answer:
The black death is estimated to have killed 30 – 60 percent of Europe’s total population during the 14th century. The dominant explanation for black death is attributed to the outbreak of plague.

Question 3.
Where do we have high and low densities of population?
Answer:

1. Areas of high density (above 50 people per sq.km) – East Asia, South Asia, northwest Europe and Eastern North America.
2. Areas of low density (less than 10 people per sq.km) – Central Africa, Western Australia, Northern Russia, Canada, etc.

Question 4.
What is Green House effect?
Answer:
Global warming is caused by the increase of green house gases such as carbondioxide, methane, water vapour and Chloro Fluoro Carbons(CFC), carbon monoxide, photo chemical oxidants and hydrocarbons, which are responsible for the heat retention ability of the atmosphere. Global warming causes climatic change, ozone layer depletion, rise in sea level and drowning of coastal inhabited land, melting of ice, etc., They are posing an even greater threat to human existence and so, man must start thinking of protecting the environment from pollution.

Question 5.
Write any two ways of how the locals and the government restored Palk Bay. Restoration of Palk Bay
Answer:
Local communities, government and civic organisations all came together not just to conserve the remaining mangroves, but also to restore it.

• Saplings of native species of plants and trees are being grown, planted and cared for.
• Live colonies of coral from the Gulf of Mannar Biosphere Reserve are being transplanted to Palk Bay. The existing mangroves and the region are being mapped and the way land is used around the mangrove is being studied.
• The local communities are actively involved in the conservation and restoration of the mangroves. Education and awareness programmes about mangrove ecosystem are being undertaken.

Question 6.
Define

1. Population growth
2. Census
3. Sustainable Development.

Answer:

1. Population growth: Population growth refers to an increase in the number of people who reside in a particular area during a particular period.
2. Census: It is an official enumeration of population carried out periodically, It records information about the characteristics of population such as age, sex, literacy and occupation.
3. Sustainable Development : Sustainable development is a development that meets the needs of the present without compromising the ability of future generation to meet their own needs.

V. Distinguish the following:

Question 1.
Birth rate and Death Rate
Answer:

Birth Rate	Death Rate
Number of live births per 1000 people in a year	Number of deaths under one year of age for every 1000 live births in a year

Question 2.
Emigration and Immigration
Answer:

Emigration Immigration	Emigration Immigration
Emigration means moving out or to leave a place.	Immigration means to enter or come into a new country for the purpose of settling there.

Question 3.
Rural settlement and urban settlement
Answer:

Rural Settlement	Urban Settlement
Any settlement where most of the people are engaged in primary activities like agriculture, forestry, mining and fishery is known as a rural settlement.	Urban is the term related to cities and towns where people are primarily engaged in non-agricultural activities, such as secondary, tertiary and quartemary activities.
The most important and unique feature of rural settlements is the vast, open spaces with green, pollution-free environment.	The common characteristic feature of an urban unit is that they are compact, congested and liable to a large number of population.

Question 4.
Metropolitan and Mega cities
Answer:

Metropolitan	Mega cities
Cities accommodating population between 10 lakhs and 50 lakhs are metropolitan cities. E.g.: Madurai	Cities with more than 50 lakh population are called Megacities. E.g.: Greater Chennai

Question 5.
Primary Activities Secondary Activities
Answer:

Primary Activities	Secondary Activities
Primary Activities pertaining to the extraction of raw materials from the earth’s surface. For example food gathering, hunting, lumbering, fishing, cattle rearing, mining and agriculture.	Secondary Activities transform raw materials into finished goods. For example Iron and Steel industries, automobile manufacturing, etc.

VI. Give reasons for the following:

Question 1.
Reforestation is encouraged throughout the world.
Answer:

1. Planting new trees can help to reduce the amount of CO₂ in the air.
2. Gases like Carbon dioxide and methane are major contributors to the changing climate.
3. Reforestation is an effective mitigation strategy to fight global warming.
4. Reforestation can help to restore what the erosion has damaged.

Question 2.
Acid rain destroys the ecosystem.
Answer:
When pollutants combine with water vapour in the presence of sunlight and oxygen, they form dilute sulphuric and nitric acids in the atmosphere. When this mixture precipitates from the atmosphere, it is called acid rain. This would cause lot of damages to life and property. It would affect the health of humans and animals, alter the constituents of water bodies, plants and trees may die as it deteriorates the soil quality and many more damages to nature.

Question 3.
The economy of the quaternary sector is called the knowledge economy.
Answer:

1. The quaternary sector of the economy is a way to describe a knowledge-based part of the economy.
2. It typically includes knowledge-oriented economic sectors such as information technology, media, research, and development.
3. It is based on knowledge and skill.
4. It consists of intellectual industries providing information services such as computing and ICT.

Question 4.
Population growth has to be brought under control.
Answer:
Population growth leads to high competition for all available resources. It leads to poor quality of life, education, food supply, low income and so on. The resources of Earth may exhaust one day and would lead to the end of mankind.

Question 5.
Sustainable development growth has been set to protect the planet.
Answer:

1. Sustainable development is the organising principle for meeting human development goals.
2. At the same time sustaining the ability of natural systems to provide the natural resources and ecosystem services upon which the economy and society depend.
3. In September 2015, the limited Nations General Assembly firmly adopted the “Universal, integrated and transformative” 2030 Agenda for Sustainable Development, a set of 17 sustainable Development goals (SDGs)
4. The goals are to be implemented and achieved in every country from the year 2016 to 2030.

VII. Answer in a paragraph:

Question 1.
Explain the factors affecting the distribution of the population.
Answer:
Population distribution refers to the way in which people are spread out across the earth surface. The world population is not uniformly distributed, owing to the following factors.
(a) Physical factors:
It includes temperature, rainfall, Soil, relief, water, natural vegetation, distribution of minerals and availability of energy resources.

(b) Historical factors:
Regions with historical importance (river valley civilizations, war and constant invasions fall under historical factors responsible for population distribution.

(c) Economic factors:
Educational Institutions, employment opportunities, manufacturing industries, luxurious amenities, trade and commerce and other facilities encourage dense population in an area.

Question 2.
Describe the patterns of rural settlement with neat diagrams.
Answer:
Rectangular pattern:
Rectangular pattern of settlements are found in plain areas or valleys. The roads are rectangular and cut each other at right angles.

Linear pattern:
In a linear pattern, the houses are located along a road, railway line and along the edge of the river valley or along a levee.

Circular or semicircular pattern:
The pattern of settlement that is found around the lakes, ponds and sea coasts are called circular or semi circular pattern.

Star-like pattern:
Where several metalled or unmetalled roads converge, star-shaped settlements develop. In the star-shaped settlements, houses are spread out along the sides of roads in all directions.

Triangular pattern:
Triangular patterns of rural settlement generally develop at the confluence of rivers.

T-Shaped, Y-Shaped, Cross-Shaped or
Cruciform settlements:
T-shaped settlements develop at trijunctions of the roads (T), while Y-shaped settlements emerge as the places where two roads converge with the third one. Cruciform settlements develop on the cross-roads which extend in all four directions.

Nebular pattern:
The arrangement of roads is almost circular which ends at the central location or nucleus of the settlement around the house of the main landlord of the village or around a mosque, temple or church.

VIII. HOTS:

Question 1.
Study your area and write down its settlement pattern.
Answer:

1. My area is Velachery, Chennai – 42.
2. It was developed after late 1990, in the Southern axis radiating out of the city.
3. It was built over a complex of low-lying wetlands.
4. In an already sunken Velachery, repeated road repairs had led to the roads increasing in height.
5. Lifting houses to escape floods.
6. Though Velachery is still a low lying area and the rainy season will be bad, it wouldn’t be as bad as before.
7. It is a place where we can get all facilities like transport, shopping, restaurants, hair parlours etc., within 1 km

IX. Map skill:

A. On the outline map of the world mark the following.
1. An area of the high density of population in Europe
2. An area of the low density of population in Australia
3. PalkBay
4. A fracking banned country
5. England – A country affected by ‘black death’
6. Denmark – First country where the modem census was conducted «
7. River Hwang Ho

B. On the outline map of Tamil Nadu mark the following.

1. A metropolitan city
2. A district with 7857 people per sq. km.
3. Gulf of Mannar
4. Palk Strait

Man and Environment ADDITIONAL QUESTIONS

I. Choose the correct answer.

Question 1.
The interaction between man as an individual with his family, occupation and society is ……..
(a) Natural Environment
(b) Human Environment
(c) Man-made Environment
(d) None of these
Answer:
(b) Human Environment

Question 2.
The physical factor is ………..
(a) temperature
(b) war
(c) trade
(d) commerce
Answer:
(a) temperature

Question 3.
The economical factor is ……..
(a) rainfall
(b) water
(c) soil
(d) luxurious amenities
Answer:
(d) luxurious amenities

Question 4.
To enter (or) come into a new country for the purpose of settling there is known as ………..
(a) internal migration
(b) emigration
(c) immigration
(d) none of these
Answer:
(c) immigration

Question 5.
The rural settlement that is found at the confluence of rivers is ……….
(a) linear pattern
(b) circular pattern
(c) starlike pattern
(d) triangular pattern
Answer:
(d) triangular pattern

Question 6.
Transforming raw materials into finished goods is an activity.
(a) primary
(b) secondary
(c) tertiary
(d) quinary
Answer:
(b) secondary

Question 7.
…….. is man-made pollution.
(a) Vehicular emission
(b) Wind erosion
(c) Pollen disposal
(d) Evaporation of organic compounds
Answer:
(a) Vehicular emission

Question 8.
Dry recyclable wastes are ……..
(a) food products
(b) packing plastics
(c) diapers
(d) mobiles
Answer:
(b) packing plastics

Question 9.
Van Mahotsav is a weeklong festival celebrated between ………
(a) 1^st and 7^th July
(b) 1^st and 7^th June
(c) 1^st and 7^th August
(d) 1^st and 7^th September
Answer:
(a) 1^st and 7^th July

Question 10.
…… disease is caused by water pollution.
(a) Hypertension
(b) Mental illness
(c) Stress
(d) Diarrhoea
Answer:
(d) Diarrhoea

II. Consider the given statements and choose the right option given below:

Question 1.
Assertion (A): Noise pollution is basically a problem in urban areas, industrial areas, transport areas due to bombardment, traffic, etc.
Reason (R): It has an impact on the habitat of animals migration and health of inhabitants.
(a) A and R are correct and A explains R
(b) A and R are correct and A does not explain R
(c) A is incorrect and R is correct
(d) Both A and R are incorrect
Answer:
(a) A and R are correct and A explains R

Question 2.
Assertion (A): Things used for domestic purposes can be reused and recycled.
Reason (R): Organic waste matter should be disposed of far away from settlements.
(a) Both A and R are incorrect
(b) Both A and R are correct
(c) A is correct and R is wrong
(d) A and R are correct and A explains R
Answer:
(b) Both A and R are correct

III. Match the following:

Answers:
1. (e)
2. (a)
3. (b)
4. (c)
5. (d)

IV. Fill in the blanks.
1. …….. is the statistical study of the human population.
2. ……. is an official enumeration of the population carried out periodically.
3. …… is a condition when a country has more people than its resources to sustain.
4. Cities with more than 50 lakh population are called ……..
5. ……… Activities pertaining to the extraction of raw materials from the earth’s surface.
6. …….. is a poisonous gas made up of molecules consisting three oxygen atoms.
7. ……. refers to the process of increase in urban population and urban areas in a country.
8. Economic sustainability is successfully implemented through strong ………
Answers:
1. Demography
2. Census
3. Overpopulation
4. megacities
5. Primary
6. Ozone
7. Urbanisation
8. Public Distribution System

V. Answer the following in brief.

Question 1.
Define Environment.
Answer:
The environment is a set of relationships between man and nature. Man has survived through the ages, dwelling within his surrounding called the environment.

Question 2.
Write a short note on “Human Environment”.
Answer:
Human environment is defined as the interaction between man as an individual, with his family, occupation, and society. It is also related to various cultural aspects such as education, religion, economics and politics.

Question 3.
What is Demography?
Answer:
In ancient Greek, ‘demos’ means people and ‘graphis’ means study Of measurement: So, ‘Demography’is the statistical study of human population.

Question 4.
What does population distribution refer to?
Answer:
Population distribution refers to the way in which people are spread out across the earth’s surface.

Question 5.
What do you mean by Nebular pattern of road arrangement?
Answer:
The arrangement of roads is almost circular which ends at the central location or nucleus of the settlement around the house of the main landlord of the village or around a mosque, temple or church.

Question 6.
Mention the patterns of Rural Settlement.
Answer:

1. Rectangular pattern
2. Linear pattern
3. Circular or semicircular pattern
4. Star-like pattern
5. Triangular pattern
6. T-Shaped, Y-Shaped, Cross-Shaped or Cruciform settlements
7. Nebular pattern

Question 7.
What are the control measures for Noise pollution?
Answer:
The control measures of noise pollution are:

1. Development of green belt vegetation.
2. Installation of decibel meters along highways and in places of public gatherings.
3. Planting trees along the compound wall to protect houses.

Question 8.
State the problems of urbanisation.
Answer:
As the town expands, it mounts more pressure on the transport system, water supplies, sewage, and profuse disposal. The overall development creates problems like air pollution, water pollution, traffic congestion and noise pollution, etc., This disturbed environment affects human beings as mental illness, heart troubles, breathing problems, etc.

Question 9.
Classify wastes.
Answer:
Wastes can be classified into five types, which are commonly found around the house. These include liquid waste, solid rubbish, organic waste, recyclable rubbish and hazardous waste like e-waste.

Question 10.
What do you mean by Environmental Sustainability?
Answer:
Environmental sustainability is the ability of the environment to support a defined level of environmental quality and natural resource extraction rates forever to mankind. Unnecessary disturbances to the environment should be avoided whenever possible.

VI. Distinguish the following

Question 1.
Natural Environment and Human Environment.
Answer:

Natural Environment	Human Environment
The components of natural components of the environment are lithosphere, atmosphere, hydrosphere and biosphere.	The human environment is defined as the interaction between man as an individual, with his family, occupation, and society.
This includes the biotic and abiotic components like ponds, lakes, grasslands, forests, mountains, etc.	It is related to various cultural aspects such as education, religion, economics and politics.

Question 2.
Rectangular Pattern and Linear Pattern.
Answer:

Rectangular Pattern	Linear Pattern
Rectangular patterns of settlements is found in plain areas or valleys. The roads are rectangular and cut each other at right angles.	In a linear pattern, the houses are located along a road, railway line, and along the edge of the river valley or along a levee.

Question 3.
Tertiary Activities and Quarternary Activities.
Answer:

Tertiary Activities	Quarternary Activities
Activities which by themselves do not produce goods, but support the process of production are called tertiary activities.	The activities related to Research and Development, as well as knowledge are called Quaternary activities.
For example Transport, communication, banking, storage, and trade.	For e.g. Services like a consultation, education, and banking.

Question 4.
Town and City
Answer:

Town	City
A town is generally larger than a village but smaller than a city. It has a population of less than 1 lakh.	Cities are much larger than towns and have a greater number of economic functions. The population in cities is estimated to be more than 1 lakh.
E.g.: Arakkonam near Chennai	E.g.: Coimbatore

VII. Give Reasons

Question 1.
“It is easy to add but difficult to maintain.”
Answer:

1. The population is a dynamic phenomenon where distribution and composition are constantly changing.
2. Human population increases as babies are born and decreases as people die. So it is easy to increase the number but difficult to maintain.

Question 2.
“Human settlement can be described as any temporary (or) permanent unit area”.
Answer:

1. During the early days man preferred tree branches, caves, pits (or) even rock cuts as his shelter.
2. Slowly settlements came into existence.
3. Later small settlements developed into villages, towns, cities. So he started living in settled areas.

Question 3.
“We must use forest products properly”.
Answer:
Besides providing habitats for animals and livelihoods for humans, forest products are one of the most essential things in our day to day life. Therefore we must use forest products properly.

Question 4.
“Pollution is an unfavourable modification of the natural world”.
Answer:
Pollute means to degrade or to make dirty. It is caused entirely (or) partly due to direct (or) indirect actions of human beings. So pollution is an unfavourable modification of the natural world.

Question 5.
Why do we get impervious diseases like skin cancer, blindness, loss of plankton?
Answer:
Due to the depletion of the ozone layer, UV rays fall on the earth’s surface and leads to impervious diseases like skin cancer, blindness, loss of plankton etc.

VIII. Answer in a paragraph.

Question 1.
Define Sustainable Development. Explain Social Sustainability and Economic Sustainability.
Answer:
“Sustainable development is a development that meets the needs of the present without compromising the ability of future generation to meet their own needs”. For sustainable development to be achieved, it is crucial to harmonize three core elements: economic growth, social aspects and environmental protection. These elements are interconnected and are crucial for the wellbeing of individuals and societies. To achieve true sustainability, we need to balance the economic, social, and environmental factors of sustainability in equal harmony.

Social Sustainability
The ability of a social system such as a country, family, or organization to function at a defined level of social well-being and harmony is called social sustainability. Problems like war, endemic poverty, widespread injustice, and low education rates are symptoms of a system in socially unsustainable. The balancing capacity of a government in maintaining peaceful existence towards other countries and at the same time providing the requirements of its citizens without affecting the environment creates social sustainability.

Economic Sustainability
The people on earth consume far more than what is their fair share.

• Economic sustainability is successfully implemented through a strong Public Distribution System.
• Economic sustainability ensures that our economic growth maintains a healthy balance with our ecosystem.

You can Download Samacheer Kalvi 10th Social Science Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 10th Social Science Geography Solutions Chapter 5 India: Population, Transport, Communication, and Trade

India: Population, Transport, Communication, and Trade Textual Exercise

I. Choose the correct answer.

Question 1.
The scientific study of different aspects of population is called ……..
(a) Photography
(b) Demography
(c) Choreography
(d) Population density
Answer:
(b) Demography

Question 2.
The state with highest literacy rate as per 2011 census is:
(a) Tamil nadu
(b) Karnataka
(c) Kerala
(d) Uttarpradesh.
Answer:
(c) Kerala

Question 3.
Human Development is measured in terms of …….
(a) Human Resource Index
(b) Per capita index
(c) Human Development Index
(d) UNDP
Answer:
(c) Human Development Index

Question 4.
…………………. transport provides door to door services.
(a) Railways
(b) Roadways
(c) Airways
(d) Waterways.
Answer:
(b) Roadways

Question 5.
The length of Golden Quadrilateral superhighways in India is
(a) 5846 km
(b) 5847 km
(c) 5849 km
(d) 5800 km
Answer:
(a) 5846 km

Question 6.
The length of navigable Inland waterways in India is:
(a) 17,500 km
(b) 5000 km
(c) 14,500 km
(d) 1000 km
Answer:
(c) 14,500 km

Question 7.
The National Remote sensing Centre (NRSC) is located at
(a) Bengaluru
(b) Chennai
(c) Delhi
(d) Hyderabad
Answer:
(d) Hyderabad

Question 8.
The transport useful in the inaccessible areas is:
(a) Roadways
(b) Railways
(c) Airways
(d) Waterways
Answer:
(c) Airways

Question 9.
Which of the following is associated with helicopter services?
(a) Air India
(b) Indian Airlines
(c) Vayudoot
(d) Pavan Hans
Answer:
(d) Pavan Hans

Question 10.
The major import item of India is:
(a) Cement
(b) Jewells
(c) Tea
(d) Petroleum
Answer:
(d) Petroleum

II. Match the following.

Answers:
1. (f)
2. (a)
3. (d)
4. (b)
5. (c)

III. Answer the following questions briefly.

Question 1.
What is Human Development?
Answer:
Dr Mahabub-ul-haq defined Human Development as “it is a process of enlarging the range of people’s choice, increasing their opportunities for education, health care, income and empowerment. It covers the full range of human choices from a sound physical environment to economic, social and political freedom”.

Question 2.
What is migration? State its types.
Answer:
It is the movement of people across regions and territories.

1. Internal migration and
2. International migration.

Question 3.
Write any four advantages of railways.
Answer:
Advantages of Railways:

1. Cater to the needs of large scale movement of traffic for freight and passengers.
2. Promotes trade, tourism, education etc.
3. Promotes National integration by bringing people together.
4. Facilitates the quick movement of perishable goods.

Question 4.
Write a note on Pipeline network transport in India.
Answer:
Pipelines are used for transporting crude oil, petroleum products and natural products and natural gas from oil fields to the refineries, factories and big thermal power plants. Pipelines are more reliable and considerably safer mode of transportation. The possibility of pilferage or product less on pipelines is almost negligible. The basic limitations of pipelines is that they are capital intensive mode of transportation.

Question 5.
State the major Inland waterways of India.
Answer:

1. Ganga – Bhagirathi – Hoogly river system between Haldia and Allahabad.
2. Stretch of the Brahmaputra river between Dhubri and Sadiya National Waterway.
3. The waterway between Kollam and Kottapuram – the first national waterway.

Question 6.
What is communication? What are its types?
Answer:
Communication refers to exchange of ideas, messages, emotions, either written or oral, from one place to another.
Types of communications are :

1. personal communication and
2. mass communication.

Question 7.
Define “International trade”.
Answer:
Trade carried on between two or more countries is called “International trade”. It is also called as external trade or foreign trade. It has two components Exports and Imports.

Question 8.
State the merits of Roadways.
Answer:

1. Cost of construction of roads is much lower.
2. Provides door to door services thus the cost of loading and unloading is much lower.
3. Used as feeder to other modes of transport to reach any destination be it railway station, sea port or airport, one need to travel through roads.

IV. Distinguish between.

Question 1.
The density of population and growth of population.
Answer:

Question 2.
Personal communication and mass communication.
Answer:

Question 3.
Print Media and Electronic Media.
Answer:

Question 4.
Roadways and Railways.
Answer:

Question 5.
Waterways Airways
Answer:

Question 6.
Internal trade and International trade.
Answer:

V. Answer the following in a paragraph.

Question 1.
What is urbanization? Explain its impacts.
Answer:
“The process of society’s transformation from rural to urban is known as urbanization”.

Impacts of Urbanization:

1. Overcrowding in urban centres.
2. It creates urban sprawl.
3. It leads to the formation of slums.
4. Shortage of houses in urban areas.
5. It creates water scarcity in the cities.
6. It creates drainage problem.
7. It poses the problem of solid waste management.
8. It increases traffic congestion in cities.
9. It increases the rate of crime.

A rapid rate of urbanization in society is taken as an indicator of its economic development.

Question 2.
Explain the importances of satellite communication in India.
Answer:
Satellite images are used for weather forecasting, monitory of natural calamities, surveillance of border areas etc. The communication through satellites emerged as a new era in communication in our country after the establishment of Indian Space Research Organization (ISRO) in 1969. Satellite systems in India can be grouped into two on the basis of two satellites namely “Indian National Satellite” (INSAT) and “Indian Remote Sensing Satellite” (IRS). These satellites collect data in several spectral band and transmit there to ground stations for various uses. The communication and remote sensing satellites INSAT and IRS have revolutionized India’s communication system. Metrological studies and natural resource management.

The National Remote Sensing Agency (NRSA) at Hyderabad provides facilities for acquisition of data and its processing. There is no doubt that India has irrefatably arrived as a space power in the world. The INSAT series are used for relaying signals to television, telephone, radio, mobile phone. It is also useful in weather detection, internet. The INSAT series GSAT series, GSAT series KALPANA -1, HAMSAT, EDUSAT are the major communication satellite used for communication purpose. GSAT – 7A is the recent launch for communication programs. INSAT – IB launched on 30th August, 1983 is the first communication satellite in INSAT series.

Question 3.
Bring out the distribution and density of population in India.
Answer:
The term “Population Distribution” refers to the way the people are spaced over the earth’s surface.

The distribution of population in India is unevenly distributed due to the vast variation in the availability of resources.

Factors that affect the distribution of population are: Terrain, climate, soil, water bodies, mineral resources, industries, transport and urbanization.

Areas of high concentration of population: Industrial centres and the areas of good agricultural lands.

Areas of thin population: high mountains, arid lands, thickly forested areas and some remote comers and some areas are even uninhabited.

Most populous states in India: Uttar Pradesh is the most populous state in India (199.5 million) followed by Maharashtra (112.3 million), Bihar (103.8 million) West Bengal (91.3 million) and the combined Andhra Pradesh (84.6 million).

Least populated State: Sikkim (0.61 million).

Union territory with high population: Delhi (16.75 million). Union territory with least population – Lakshadweep (64,073).

Question 4.
Explain the process of measuring Human Development.
Answer:
Dr. Mahabub – ul – Haq defined as “It is a process of enlarging the range of people’s choice, increasing their opportunities for education, health care, income and empowerment”. Human
Development Index (HDI) is a composite index focusing on three basic dimensions of human development.

1. Health – life expectancy at birth,
2. Education – expected years of schooling for school age children and average years of schooling for the adult population,
3. Income – Measured by gross national income and per capita income.

Question 5.
Classify and explain the roadways in India.
Answer:
Roadways play an important role in carrying goods and passengers for short, medium and long distances. It is highly suitable for short-distance services.

For the purpose of construction and maintenance Roadways in India are classified into:

1. National Highways (NH)
2. State Highways (SH)
3. District Roads
4. Rural Roads (Village roads)
5. Border Roads
6. International Highways

National Highways:

1. Ministry of Road Transport and Highways of India is responsible for the development and maintenance of the National Highways in India.
2. These Highways are connecting capitals of states, major ports, rail junctions, industrial and tourist centres.
3. The total length of the National Highways in India is 1,01,011 Km which accounts for 1.8% of total road network length in 2016.
4. The longest National Highway NH-7 runs from Varanasi (U.R) to Kanyakumari (T.N) to a distance of 2369 km.
5. The shortest National Highway is NH-47A, runs from Emakulum to Kochi port (Willington Island) covering a distance of 6 km.

State Highways:

1. These roads are administered and financed by State Governments.
2. These highways link important cities, towns and district headquarters within the state and connect them with national highways or highways of neighbouring states.
3. State highways run to a length of 1,76,166 km as of 2016.

District Roads:

1. District Roads are constructed and maintained by the Public Works Department of the states.
2. District Roads provide connectivity between the district and taluk headquarters with the state highways and national highways.
3. The total length of the road is 5,61,940 km in 2016.
4. Rural Roads (Village Roads): They are maintained by village Panchayats.
5. It links different villages with their neighbouring towns.
6. Rural roads connectivity is a key component of Rural development.
7. The total length of Rural roads in India is 39,35,337 km as of 2016.
8. Rural roads consists of Panchayat roads, (Zilla Parishad, Panchayat Samiti, Gram Panchayat), roads of the Pradhan Mantri Gram Sadak Yojana (PMGSY) and those constructed by the State PWDs.

Border Roads:

1. They are constructed and maintained by Border Roads Organization established in 1960 for the development of the roads of Northern and North Eastern border areas.
2. These are the roads of strategic importance in border areas.
3. The Border Road organization has constructed world’s highest road joining Chandigarh and Leh in Ladak (at an altitude 4,270 mt).
4. Golden Quadrilateral: This project was launched in 1999.
5. It connects India’s four metropolitan cities Delhi – Kolkata – Chennai Mumbai.
6. It has 4/6 lanes and of 5,846 km long.
7. North-South and East-West corridors: These two corridors intersect at Jhansi.
8. North-South Corridor connects Srinagar in Jammu and Kashmir with Kaniyakumari in Tamil Nadu (4,076 km).
9. The East-West corridor connects Silchar in Assam with port town of Porbandar in Gujarat (3,640 km).

Express ways: These are the multi lane good quality highways for high speed traffic. Eg: (a) Mumbai – Pune Road, (b) Delhi – Agra.

International Highways:

1. These Highways have been constructed with an aid from World Bank under an agreement with the Economic and Social Commission for Asia-pacific (ESCAP).
2. These roads link India with her neighbouring countries – Pakistan, Nepal, Bhutan, Bangladesh and Myanmar.

India has the second-longest road network in the world.

VI. On the outline map of India mark the following.

1. National Highway NH-7.
3. Major International Airports in India.

2. Major seaports in India.
4. Densely populated state of India.
5. State of highest literacy in India.

6. Railway zones of India

In-Text Hots Questions:

Question 1.
What could be the reason for uneven distribution of population in India?
Answer:
The uneven distribution of population in the country is the result of several factors such as physical, socio-economic and historical ones.

Physical factors: Relief, climate, water, natural, vegetation, mineral and energy resources.

Socio-economic factors: Religion, political issues economy, human settlements, transport network, industrialization, urbanization, employment opportunity etc.

Question 2.
What are the reasons for the rapid growth of population in India?
Answer:

• Widening gap between birth and death rates.
• Low age at marriage.
• High illiteracy.
• Religious attitudes towards family planning.

Question 3.
The sex ratio in our country is always unfavourable to females. Give reasons.
Answer:

1. Attitude of the people: Prestige and pride in having male child made them to prefer a male child to a female child.
2. Female infanticide: Even now in same places it is being done for fear of neglect by their family members if they give birth to a female child.
3. Future marriage expenses on female child.
4. Considered as weaker sex so will not be given opportunity to prove their ability suppressed by male domination.

Question 4.
Find out what are the functions of NHAI.
Answer:
The functions of National Highways Authority of India (NHAI) are:

• To develop, maintain and manage the national highways and any other highways vested in, or entrusted to it by the Government.
• Survey, develop, maintain and manage highways vested in, or entrusted to it.
• Construct offices or workshops and establish and maintain hotels, motels, restaurants and rest-rooms at or near the highways vested in, or entrusted to it.
• Construct residential buildings and townships for its Employees.
• Regulate and control the plying of vehicles on the highways vested in or entrusted to it for the proper management thereof.
• Provide such facilities and amenities for the users of the highways vested in, or entrusted to it as are in the opinion the Authority, necessary for the smooth flow of traffic on such highways.
• Advise the Central Government on matters relating to highways.

Question 5.
What are the highlights and benefits of the Golden Quadrilateral Highways?
Answer:
The main objective of this project is connectivity, speed and safety.

Connectivity: Connects four major metropolitan cities enhances the movement of goods and people to the industrial areas enhances job development.
Access to hinterland of agricultural areas to market areas, ports for export needs.

Speed: Reduces the travel time.

Safety: Six lanes super highways meant for safety.

This project was launched in the year 1999. Implemented by National Highway Authority of India.

Encourages the private sector companies to invest, develop and maintain these highways.

Question 6.
Why is air travel preferred in the north eastern states?
Answer:

• Due to mountains, rivers, etc. road journey becomes too long even for short distance.
• So air travel is the most feasible option and the costs are also quite low due to subsidies by the government.
• Most of the cities have regional active airports.
• Air transport is preferred mainly in the North eastern states of India.

Question 7.
Find out the major trade blocks which are useful for multilateral trade.
Answer:
Major trade blocks useful for Multilateral trade.

EU: European Union

APEC: (Asian Pacific Economic Community) .

ASEAN: (Association of South East Asian Nations)

SAPTA: (South Asian Preferential Trade Agreement)

These trade blocks made the international trade easier. All member countries who signed the agreement are treated equally. These trade blocks remove the barriers and complications arose between nations in international trade.

Activity:

Question 1.
Prepare a seminar topic about “Role of Railways in Indian Economy”.
Answer:
Role of Railways in Indian Economy

• Railways are the principle mode of transportation for freight and passengers in India.
• Railways also make it possible to conduct multifarious activities like business, sight seeing, pilgrimage along with transportation of goods over longer distances.
• Railways in India bind the economic life of the country as well as accelerate the development of industry and agriculture.
• The distribution pattern of the railway netw ork in the country has been largely influenced by physiographic, economic and administrative factors.

Question 2.
Collect the names for different types of goods and differentiate it and make a table as perishable and non-perishable goods.
Answer:
Perishable goods are foods like fresh meat, seafood, and ripe fruits.
Non-perishable are items that do not spoil or decay.
Ex. Canned goods, all pasta types, sugar, flour, curls and chips if air-sealed.

Question 3.
Collect the countries names and make it as a table of Bilateral trade and multilateral trade countries.
Answer:

Find Out:

The important National Highways in India and label it on the outline map of India.

The important National Highways in India are:
NH-6- Hazira to Kolkata (via Nagpur, Raipur, Sambalpur and Dhule)
NH-7 -Varanasi to Kanyakumari (Nagpur, Bangaluru and Madurai
NH-8 – Delhi to Mumbai (Jaipur, Ahmedabad and Vadodara)
NH-9 – Pune to Machilipatnam and Hyderabad, Vijayawada

The important National Highways in India.

India: Population, Transport, Communication, and Trade Additional Questions

I. Choose the correct answer.

Question 1.
India is the ……. most populous country in the world.
(a) first
(b) second
(c) sixth
Answer:
(b) second

Question 2.
The …………………. is the least populous state.
(a) Assam
(b) Goa
(c) Sikkim
(d) Arunachal Pradesh
Answer:
(c) Sikkim

Question 3.
Postal service and telegraph are some of the ………. communication.
(a) personal
(b) professional
(c) mass
Answer:
(a) personal

Question 4.
In India the year of demographic divide registered negative growth rate is ………………….
(a) 1921
(b) 1931
(c) 1947
(d) 1950
Answer:
(a) 1921

Question 5.
The headquarters of the Northern Railways is ………
(a) Jabalpur
(b) Allahabad
(c) Guwahati
Answer:
(c) Guwahati

Question 6.
The National Highways Authority of India was established in:
(a) 1975
(b) 1985
(c) 1995
(d) 2005
Answer:
(c) 1995

Question 7.
The first railway line was laid between in 1853.
(a) Delhi and Kolkata
(b) Mumbai and Kolkata
(c) Mumbai and Thane
Answer:
(c) Mumbai and Thane

Question 8.
Indian Railways is organized into …………………. zones for operations and management.
(a) 15
(b) 20
(c) 16
(d) 19
Answer:
(c) 16

Question 9.
Trade blocs are created to make the ……. trade easier.
(a) Multilateral
(b) Bilateral
(c) Local
Answer:
(a) Multilateral

Question 10.
The …………………. is the fuel efficient and eco-friendly mode of transport.
(a) Roadways
(b) Railways
(c) Waterways
(d) Airways
Answer:
(c) Waterways

Question 11.
The headquarters of Indian Railways is ……..
(a) Mumbai
(b) New Delhi
(c) Nagpur
Answer:
(b) New Delhi

Question 12.
The …………………. are the most powerful means of print media.
(a) Radio
(b) Magazines
(c) Fax
(d) Newspapers
Answer:
(d) Newspapers

Question 13.
The highways connecting the four metropolitan cities – Chennai, Mumbai, Delhi and Kolkata.
(a) Six lanes super highways
(b) Expressways
(c) Border Roads
Answer:
(a) Six lanes super highways

Question 14.
Primitive method of trade was known as system.
(a) communication
(b) barter
(c) bilateral
(d) balanced
Answer:
(b) barter

Question 15.
Metro Rail transport in Chennai was introduced in …….
(a) 2015
(b) 2014
(c) 2005
Answer:
(a) 2015

Question 16.
Since 1957 All India Radio came to be called ……..
(a) Akshvani
(b) Sooriyan FM
(c) Vivith Bharathy
Answer:
(a) Akshvani

Question 17.
The Government of India merged all the Indian Airlines under ………
(a) TATA Airline
(b) National Aviation Corporation of India
(c) Airport Authority of India
Answer:
(b) National Aviation Corporation of India

Question 18.
Which mode of transportation reduces trans-shipment losses and delays.
(a) Railways
(b) Pipelines
(c) Roadways
Answer:
(b) Pipelines

Question 19.
Which of the following sates is not connected with the H.V.J. Pipeline?
(a) Madhya Pradesh
(b) Maharashtra
(c) Gujarat
Answer:
(b) Maharashtra

Question 20.
Which one of the following ports is the deepest land-locked and well protected port along the
east coast?
(a) Chennai
(b) Paradip
(c) Vishakhapatnam
Answer:
(c) Vishakhapatnam

Question 21.
Which one of the following terms is used to describe trade between two or more countries?
(a) Internal Trade
(b) International Trade
(c) Local Trade
Answer:
(b) International Trade

Question 22.
The National Highway No.l is also known as
(a) Mahatma Gandhi Marg
(b) Sher Shah Suri Marg
(c) Jawahar Lai Nehru Road
Answer:
(b) Sher Shah Suri Marg

Question 23.
Trade carried in cities, towns and villages is called
(a) External trade
(b) Local trade
(c) international trade
Answer:
(b) Local trade

Question 24.
The Indian National Highways are maintained by the department of …….
(a) State Public Works Department
(b) Zila Parishad
(c) Central Public Works Department
Answer:
(c) Central Public Works Department

Question 25.
Which one of the following organizations constructs Border roads in India?
(a) PWD
(b) CPWD
(c) NHAI
Answer:
(c) NHAI

Question 26.
World has become a global village due to which of the following?
(a) Transport and communication
(b) Engineering Industry
(c) International trade
Answer:
(a) Transport and communication

Question 27.
Border Roads Organization was established in
(a) 1950
(b) 1955
(c) 1960
Answer:
(c) 1960

Question 28.
The longest highways of India is
(a) National Highway – 8
(b) National Highway – 7
(c) National Highway – 1
Answer:
(b) National Highway – 7

Question 29.
Delhi and Mumbai are connected by …..
(a) National Highway – 1
(b) National Highway – 15
(c) National Highway – 8
Answer:
(c) National Highway – 8

Question 30.
Which Port is the major iron ore exporting port of the country?
(a) Mumbai Port
(b) Marmagoa
(c) Kandala Port
Answer:
(b) Marmagoa

Question 31.
The biggest port is …….
(a) Mumbai Port
(b) Marmagoa Port
(c) Kandala Port
Answer:
(a) Mumbai Port

Question 32.
The extreme south – western port is …….
(a) Tuticorin Port
(b) Kochi Port
(c) New Mangalore Port
Answer:
(b) Kochi Port

II. Fill in the blanks.

1. Our National Integration is strengthened by the ……
2. …… have been replaced by more powerful diesel or electric engines.
3. There are ……… major ports located on the coast line of India.
4. Crude oil, petroleum and natural gas are transported by ……….
5. The largest terrestrial network of the world is ……….
6. The latest means of communication is ………
7. The multi purpose satellite system for telecommunication is …… – INSAT
8. The roadways are able to connect most of the ……… villages.
9. It is easier to construct and maintain ………..
10. National highways are maintained by ……… Government.
11. Indian railways system is the ……… in Asia.
12. Under transport the ….. forms the lifeline of the country.
13. The city ……. is the focal point from where railway lines radiate in all directions.
14. River Ganga is navigable upto …….
15. This world has been shrunk since the introduction of ……..
Answers:
1. Railways
2. Steam Engines
3. 13
4. pipelines
5. Doordharshan
6. Satellite
7. Indian National Satellite
8. remote
9. roadways
10. Central
11. largest
12. Railways
13. Delhi
14. Varanasi
15. Internet

III. Match the following.

Answers:
(1 – c)
(2 – d)
(3 – a)
(4 – e)
(5 – b)

Answers:
(1 – d)
(2 – a)
(3 – e)
(4 – c)
(5 – b)

Answers:
(1 – e)
(2 – c)
(3 – a)
(4 – b)
(5 – d)

Answers:
(1 – d)
(2 – c)
(3 – e)
(4 – b)
(5 – a)

IV. Answer in one word.

Question 1.
What provides information regarding the population of our country?
Answer:
The Census of India.

Question 2.
When was the first Census held in India?
Answer:
1872

Question 3.
When was the first complete census taken?
Answer:
1881

Question 4.
After how many years Census is held in India?
Answer:
Census is held regularly after every tenth year.

Question 5.
Which is the most comprehensive source of demographic, social and economic data in India?
Answer:
Indian Census

Question 6.
What is the population of India according to 2001 and 2011 Census?
Answer:
India’s population size as on March 2001 stood at 1,028 million and in 2011 is 1,210 million.

Question 7.
Which is the most populous state of India?
Answer:
Uttar Pradesh

Question 8.
Which is the least populated state of India?
Answer:
Sikkim

Question 9.
Which is the least populated region of India?
Answer;
Lakshadweep

Question 10.
Name the five most populated states in India.
Answer:

1. Uttar Pradesh,
2. Maharashtra,
3. Bihar,
4. West Bengal and
5. Andhra Pradesh.

Question 11.
Define population density.
Answer
It is calculated as the number of persons per unit area.

Question 12.
Which is the least densely populated state of India?
Answer:
Andhra Pradesh with 17 persons per sq.km.

Question 13.
Name the three main processes of change of population.
Answer:
Birth rates, death rates and migration.

Question 14.
Which two countries have a higher average population density than India?
Answer:
Bangladesh and Japan.

Question 15.
What are various types of migration?
Answer:
Internal migration and International migration.

Question 16.
Define age structure.
Answer:
It refers to the number of people in different age groups in a country.

Question 17.
Define sex ratio.
Answer:
Sex ratio is defined as the number of females per 1000 males in the popultion.

Question 18.
Is sex ratio balanced in India?
Answer:
No

Question 19.
Which regions of India has the highest and lowest sex ratio as per Census 2011?
Answer:
Kerala has a sex ratio of 1084 females per 1000 males, Delhi has only 866 females per 1000 males.

Question 20.
Who is a literate?
Answer:
A person aged 7 years and above who can read and write with understanding in any language is treated as literate.

V. Distinguish between.

Question 1.
National Highways and State Highways.
Answer:

Question 2.
Exports and Imports.
Answer:

Question 3.
Village Roads and District Roads.
Answer:

Question 4.
Bilateral Trade and Multilateral Trade
Answer:

Question 5.
Birth Rate and Death Rate
Answer:

Question 6.
Favourable balance of trade and Unfavaourable balance of Trade
Answer:

VI. Answer the following questions briefly.

Question 1.
What is the position of Indian population in the World?
Answer:

1. India is the second most populous country in the world.
2. It is the home of 17.5% of world’s population.
3. One out of every six persons in the w orld is from India.
4. Our population is almost equal to the combined population of USA, Indonesia, Brazil, Pakistan, Bangladesh and Japan.

Question 2.
How is the population of India grouped?
Answer:
The population of a nation is generally grouped into three broad categories.

1. Children (below 15 years): They are economically unproductive and need to be provided with food, clothing, education and medical care.
2. Working Age (15-59 years): They are economically productive and biologically reproductive. They comprise the working population.
3. Aged (above 59 years): They can be economically productive though they may have retired.

Question 3.
What does the term “population change” refer to?
Answer:
The term “population change” refers to an increase or decrease of population of an area from one period to another period.

Question 4.
Name the three major superhighway project.
Answer:

1. Golden Quadrilateral Super Highways: It links Delhi – Kolkata – Chennai – Mumbai and Delhi by six lane Super Highways.
2. North – South Corridor: Linking Srinagar (Jammu and Kashmir) and Kanyakumari (Tamil Nadu).
3. East-West Corridor: Linking Silcher (Assam) and Porbandar (Gujarat). The major objective of these Super Highways is to reduce the time and distance between the mega cities of India.

Question 5.
Name the three major means of transport in the world?
Answer:
The three major means of transport in the world are:

1. Land transport: Roadways, Railways and pipelines.
2. Waterways: Inland waterways and ocean routes
3. Air transport: Domestic airways and International airways.

Question 6.
What is trade? What are the types of ti;ade?
Answer:

1. Trade is an act or process of buying, selling or exchanging goods and services.
2. Types of trades are
   • Internal trade
   • International trade.

Question 7.
Write about the merits of air transport.
Answer:
Airways are the quickest, costliest most modem and comfortable means of transport.

1. Facilitates connectivity on a regional, national and international scale.
2. Made accessibility by connecting difficult terrains like high mountains and deserts.
3. It carries passengers, freight and mail.
4. Air transport plays a key role in times of emergency, during the time of natural and man made calamities like floods, epidemics and wars.

Question 8.
What are the merits of pipeline transport?
Answer:

1. It can be laid through difficult terrain as well as under water.
2. Initial cost of laying pipelines is high but subsequent cost for maintenance and operation is low.
3. It ensures steady supply and minimizes transhipment losses and delays.
4. Pipeline operation involves very low consumption of energy.

Question 9.
What are the different kinds of mail services introduced by Department of posts?
Answer:

1. Cards and envelopes are considered first-class mail and airlifted between ‘ stations both land and air.
2. The second class mail includes-book packets, registered newspapers and periodicals, carried by surface mail covering land and water transport.
3. Recently six mail channels have been introduced to facilitate quick delivery of mails in large towns and cities. They are Rajdhani channel, Metro Channel, Green Channel, Business Channel, Bulk mail Channel

Question 10.
Explain MRTS (Metro Rail System).
Answer:

1. The Mass Rapid Transit System is an elevated line of the suburban railways in Chennai.
2. This Railway is administrated by the state owned Southern Railway.
3. This railway line currently runs from Chennai beach to Velachery covering 17 stations for a distance of 25 km.

Question 11.
What do you mean by Foreign Exchange?
Answer:
Foreign Exchange is the mechanism or process by which payments between any two places operating under different national currency systems are effected without passing of actual money or gold etc.

Question 12.
What are the four ship building yards in India?
Answer:

1. Hindustan Shipyard at Vishakhapatnam.
2. Garden reach workshop at Kolkata.
3. Mazagaon Dock at Mumbai.
4. Kochin Ship Yard and Kochi.

Question 13.
Define the term Dependency Ratio.
Answer:
The ratio between the economically active and economically inactive of population is termed as Dependency Ratio.

VII. Answer in a paragraph:

Question 1.
Define population. Why there is a need to study population?
Answer:

1. The total number of people residing in a country at a specified period of time is called “population” of that country. The study of population is known as Demography.
2. The human population has many components but the most fundamental are its numbers, composition, distribution and density. The study on these aspects also would reveal the work force of the country.
3. Population census of India provides the detailed information about the demography of India.

Question 2.
Name the major National Waterways of our country.
Answer:

1. The Ganga river between Allahabad and Haldia (1620 km). National Waterways No. 1
2. The Brahmaputra river between Sadiya and Dhubri (891 km) – National Waterways No.2
3. The West Coast Canal in Kerala (Kottapuram – Komman – Udyogmandal and Champakkara Canals – 205 km) – National Waterways No.3
4. Specified stretches of Godavari and Krishna rivers along with Kakinada Puducherry Stretch of canals (1078 km) – National Waterways No.4 (v) Specified stretches of river Brahmani along with Matai river, delta channels of Mahanadi and Brahmani rivers and East Coast Canal (588 km) – National Waterways No.5.

There are some other inland waterways on which substantial transportation taken place. These are Mandavi, Zuari and cumberjua, Sundarbans, Barak, backwaters of Kerala and tidal stretches of some other rivers.

Question 3.
Explain about the population composition.
Answer:
Population composition refers to characteristics such as age, sex, marital status, caste, language, education, occupation etc.

The study of composition of population helps us to understand the Social, economic and demographic structure of population.

Age Composition: Population of a county is generally grouped into three broad categories.

1. Children less than 15 years of age (29.5%)
2. The people above 60years (8%)
3. These two categories falls under dependent population (37,5%)
4. Independent population 16 – 59 years (62.5%)

It shows that our country has enormous man power i.e., working force.

Sex Ratio: Sex ratio is defined as the number of females per 1000 male population.

This is an important social indicator to measure the extent of equality between males and females in a society at a given rime.

According to 2011 census the sex ratio of the country is 940 females per 1000 males.

Literacy Rate: It is an important indicator of quality of people.

The people who are able to read and write are known as literates. The percentage of literate people to the total population is termed as literacy rate.

As per 2011 India’s literacy rate is 74.04%.

Occupational Structure: The economically active part of a country’s population are termed as workers.

They are placed under three categories as main workers, marginal workers and non workers.

Main workers are those who worked for the major part of the preceding year at least 6 months or 183 days.

Who worked less than six months are marginal.

People who have not worked at all comes under non workers.

In India as per 2011 census 75.23% are main workers and 24.77% of the people belong to marginal workers.

Question 4.
What are the means of transportation and communication called the lifelines of a nation and its economy?
Answer:
The development of a country depends upon the production of goods and services as well as their movement to their destination. Transport plays an important role in the economy. Because of transport raw materials reach to the factory or industry, and finally finished products reach to the consumer. It has helped in both production and distribution of goods. Hence, all efficient means of transport are prerequisites for fast development.

India is well – linked with the rest of the world despite its vast size, diversity and linguistic and socio-cultural plurality. Railways, airways, waterways, newspapers, radio, television, cinema and internet etc., have been contributing to its socio-economic progress in many ways. The trades from local to international levels have added to the vitality of its economy. It has also enriched our life and added substantially to growing amenities and facilities for the comforts of life. Hence, it is right to say that means of transportation and communication are the lifelines of a nation and its economy.

You can Download Samacheer Kalvi 11th Maths Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 11th Maths Solutions Chapter 8 Vector Algebra – I Ex 8.1

Question 1.
Represent graphically the displacement of
(i) 45 cm 30 ° north of east
(ii) 80 km, 60° south of west
Solution:
(i) 45 cm 30 0 north of east

(ii) 80 km 60° south of west

Question 2.
Prove that the relation R defined on the set V of all vectors by \(\vec{a}\) R \(\vec{b}\) if \(\vec{a}=\vec{b}\) is an equivalence relation on V.
Solution:
\(\vec{a}\) R \(\vec{b}\) is given as \(\vec{a}=\vec{b}\).
(i) \(\vec{a}\) = \(\vec{a}\) ⇒ \(\vec{a}\) R \(\vec{a}\)
(i.e.,) the relation is reflexive.

(ii) \(\vec{a}=\vec{b}\) ⇒ \(\vec{b}\) = \(\vec{a}\)
(i.e.,) \(\vec{a}\) R \(\vec{b}\) – \(\vec{b}\) R \(\vec{a}\)
So, the relation is symmetric.

(iii) \(\vec{a}=\vec{b} ; \vec{b}=\vec{c} \Rightarrow \vec{a}=\vec{c}\)
(i.e) \(\vec{a}\) R \(\vec{b}\) ; \(\vec{b}\) R \(\vec{c}\) ⇒ \(\vec{a}\) R \(\vec{c}\)
So the given relation is transitive
So, it is an equivalence relation.

Question 3.
Let \(\vec{a}\) and \(\vec{a}\) be the position vectors of points A and B. Prove that the position vectors of the points which trisect the line segment AB are
Solution:

Question 4.
If D and E are the midpoints of the sides AB and AC of a triangle ABC, prove that

Solution:

Question 5.
Prove that the line segment joining the midpoints of two sides of a triangle is parallel to the third side whose length is half of the length of the third side.
Solution:

Question 6.
Prove that the line segments joining the midpoints of the adjacent sides of a quadrilateral form a parallelogram.
Solution:

In a quadrilateral when opposite sides are equal and parallel it is a parallelogram So, PQRS is a parallelogram, from (1) and (2).

Question 7.
If \(\vec{a}\) and \(\vec{b}\) represent a side and a diagonal of a parallelogram, find the other sides and the other diagonal.
Solution:
OABC is a parallelogram where

Question 8.
If \(\overrightarrow{\mathrm{PO}}+\overrightarrow{\mathrm{OQ}}=\overrightarrow{\mathrm{QO}}+\overrightarrow{\mathrm{OR}}\), prove that the points P, Q, R are collinear.
Solution:

But Q is a common point.
⇒ P, Q, R are collinear.

Question 9.
If D is the midpoint of the side BC of a triangle ABC, prove that \(\overrightarrow{\mathbf{A B}}+\overrightarrow{\mathbf{A C}}=2 \overrightarrow{\mathbf{A D}}\)
Solution:
D is the midpoint of ∆ ABC.

Question 10.
If G is the centroid of a triangle ABC, prove that \(\overrightarrow{\mathrm{GA}}+\overrightarrow{\mathrm{GB}}+\overrightarrow{\mathrm{GC}}=0\)
Solution:
For any triangle ABC,
\(\overrightarrow{\mathrm{GA}}+\overrightarrow{\mathrm{GB}}+\overrightarrow{\mathrm{GC}}=0\)
Now G is the centroid of ∆ABC, which divides the medians (AD, BE and CF) in the ratio 2 : 1.

Question 11.
Let A, B, and C be the vertices of a triangle. Let D, E, and F be the midpoints of the sides BC, CA, and AB respectively. Show that \(\overrightarrow{\mathrm{AD}}+\overrightarrow{\mathrm{BE}}+\overrightarrow{\mathrm{CF}}=\overrightarrow{0}\)
Solution:
In ∆ABC, D, E, F are the midpoints of BC, CA, and AB respectively.

Question 12.
If ABCD is a quadrilateral and E and F are the midpoints of AC and BD respectively, then prove that \(\overrightarrow{\mathbf{A B}}+\overrightarrow{\mathbf{A D}}+\overrightarrow{\mathbf{C B}}+\overrightarrow{\mathbf{C D}}=4 \overrightarrow{\mathrm{EF}}\)
Solution:
ABCD is a quadrilateral in which E and F are the midpoints of AC and BD respectively.

Samacheer Kalvi 11th Maths Solutions Chapter 8 Vector Algebra – I Ex 8.1 Additional Problems

Question 1.
Shown that the points with position vectors are collinear.
Solution:
To prove the points P, Q, R are collinear we have to prove that \(\overrightarrow{\mathrm{PQ}}\) = t \(\overrightarrow{\mathrm{PR}}\) where t is a scalar.
Let the given points be P, Q, R.

So, the points P, Q, R are collinear (i.e,) the given points are collinear.

Question 2.
If ABC and A’B’C’ are two triangles and G, G’ be their corresponding centroids, prove that \(\overrightarrow{\mathrm{AA}^{\prime}}+\overrightarrow{\mathrm{BB}^{\prime}}+\overrightarrow{\mathrm{CC}^{\prime}}=3 \overrightarrow{\mathrm{GG}}\)
Solution:
Let O be the origin.
We know when G is the centroid of ∆ ABC,

Question 3.
Prove using vectors the mid-points of two opposite sides of a quadrilateral and the mid-points of the diagonals are the vertices of a parallelogram.
Solution:
ABCD is a quadrilateral with position vectors
OA = \(\vec{a}\), OB = \(\vec{b}\), OC = \(\vec{c}\) and OD = \(\vec{d}\)
P is the midpoint of BC and R is the midpoint of AD.
Q is the midpoint of AC and S is the midpoint of BD.
To prove PQRS is a parallelogram. We have to prove that \(\overrightarrow{\mathrm{PQ}}=\overrightarrow{\mathrm{SR}}\)

You can Download Samacheer Kalvi 9th Social Science Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 9th Social Science Geography Solutions Chapter 3 Atmosphere

Atmosphere Textual Exercise

I. Choose the Best Answer.

Question 1.
…………… is the most important gas for the survival of living
(a) Helium
(b) carbon-di-oxide
(c) oxygen
(d) methane
Answer:
(c) oxygen

Question 2.
The lowest layer of the atmosphere is ……………
(a) Troposphere
(b) Stratosphere
(c) Exosphere
(d) Mesosphere
Answer:
(a) Troposphere

Question 3.
…………. reflects radio waves.
(a) Exosphere
(b) Ionosphere
(c) Mesosphere
(d) Stratosphere
Answer:
(c) Mesosphere

Question 4.
The average global surface temperature is …………….
(a) 12°c
(b) 13°c
(c) 14°c
(d) 15°c
Answer:
(b) 13°c

Question 5.
The process of change of state of water from gaseous to liquid state is called ……………..
(a) Precipitation
(b) evaporation
(c) transpiration
(d) condensation
Answer:
(d) condensation

Question 6.
The …………… is the chief energy source of the Earth.
(a) Sun
(b) Moon
(c) Stars
(d) clouds
Answer:
(a) Sun

Question 7.
All types of clouds are found in the ……………….
(a) Troposphere
(b) Ionosphere
(c) Mesosphere.
(d) Exosphere
Answer:
(a) Troposphere

Question 8.
…………….. clouds are called ‘Sheep clouds’.
(a) Alto-cumulus
(b) Alto-Stratus
(c) Nimbo-stratus
(d) Cirro-cumulus
Answer:
(a) Alto-cumulus

Question 9.
The Monsoons are ……………
(a) Prevailing winds
(b) Periodic winds
(c) local winds
(d) none of the above
Answer:
(b) Periodic winds

Question 10.
Dew in the form of ice crystals is called ………….
(a) frost
(b) fog
(c) mist
(d) sleet
Answer:
(d) sleet

Question 11.
………………. is called the eye of the storm.
(a) Pressure
(b) wind
(c) cyclones
(d) snow
Answer:
(c) cyclones

Question 12.
The vertical movement of air is called ……………
(a) Wind
(b) storm
(c) Air current
(d) drift
Answer:
(c) Air current

II. Match the following.

Answer:
1. (e)
2. (d)
3. (a)
4. (b)
5. (c)
6. (g)
7. (f)

III. Answer the following questions briefly.

Question 1.
Define the atmosphere.
Answer:

1. The blanket of air that surrounds the Earth is called the atmosphere.
2. It is held close to the earth by gravitational attraction.
3. The atmosphere is a mixture of gases, water vapour, and dust particles in different proportions

Question 2.
Name the different atmospheric layers.
Answer:
The different atmospheric layers are Troposphere* Stratosphere, Mesosphere, Thermosphere, and Exosphere.

Question 3.
Mention the factors that affect the climate.
Answer:
The factors that affect weather and climate are

1. Latitude or distance from the equator
2. Altitude height above the sea level
3. Nearness to the sea
4. Nature of the prevailing winds
5. Mountain barrier
6. Cloud cover
7. Ocean currents
8. Natural vegetation

Question 4.
What is insulation?
Answer:
The amount of heat received from the sun in the form of short waves is called insulation (or) incoming Solar Radiation.

Question 5.
What are isotherms?
Answer:
Some of the processes that are responsible for atmospheric heat are Radiation, Conduction, Convection, and Advection.

Question 6.
Write a short note on ‘Lapse rate’.
Answer:

• Altitude refers to the height above sea level.
• The temperature decreases at the rate of 1°C far every 165 mts of height. This is called “Normal Lapse rate”.

Question 7.
What are the processes responsible for heating the atmosphere?
Answer:
The processes responsible for heating the atmosphere are Radiation, Conduction, Convection and Advection.

Question 8.
Mention the planetary wind system of the earth.
Answer:
The winds which constantly blow in the same direction throughout the year are called the planetary winds. They are also called permanent winds (or) the prevailing winds.

Question 9.
Write a short note on:
(a) Trade winds (b) Roaring Forties
Answer:
(a) Trade winds:

1. Trade winds blow from the subtropical high-pressure belt to the Equatorial low-pressure belt in both the hemispheres.
2. They blow with great regularity, force and in a constant direction throughout the year.
3. These winds were helpful to traders, hence called trade winds.
4. As they move westwards, they become dry and do not give rainfall.

(b) Roaring Forties:

1. Westerlies are the permanent winds that blow from the tropical high-pressure belt to the subpolar low-pressure belt in both the hemispheres.
2. The velocity of westerlies become so vigorous and fast to be called Roaring Forties at 40°, Furious Fifties at 50°, and screaming Sixties at 60° latitudes.

Question 10.
How are clouds formed?
Answer:

1. A large amount of water evaporates each day from the surface of the Sea.
2. This is the principal source of atmospheric moisture.
3. Cool moisture-laden air gets collected around particles like dust, salt content from the sea, smoke, etc, and forms clouds.
4. Sometimes mixing warmer and cooler air also produces clouds.

Question 11.
What are the different types of rainfall?
Answer:

1. Rainfall is the most predominant type of precipitation.
2. Moisture laden air masses raise upwards, forms clouds, and bring rainfall.
3. Based on the mechanisms of raising the air, there are three types of rainfall.
4. They are
   • Convectional rainfall
   • Frontal or Cyclonic rainfall
   • Orographic rainfall.

Question 12.
What is Precipitation? What are the different forms of precipitation?
Answer:

1. Falling down of condensed water vapour in different forms is called Precipitation.
2. When the dew point is reached in the cloud water droplets become saturated and start to fall as Precipitation.
3. The different types of precipitation are
   • drizzle
   • rain
   • sleet
   • snow
   • hail etc.

Question 13.
Write short notes on:

1. Drizzle
2. rain
3. sleet
4. snow
5. heat

Answer:

1. Drizzle: The falling of numerous uniform minute droplets of water with a diameter of less than 0. 5 is called a driggle.
2. Rain: Rain is the most widespread and important form of precipitation in places having temperatures above the freezing point.
3. Sleet: Sleet refers to precipitation in form of pallets made up of transparent and translucent ice. This is a mixture of snow and rain.
4. Snow: Snow is formed when condensation occurs below the freezing point. It is the precipitation of opaque and semi-opaque ice crystals.
5. Heat: Heat is the energy which makes an object hot, while temperature measures the intensity of heat.

Question 14.
How are Cyclones classified?
Answer:
Cyclones Can be classified into

1. Tropical cyclones
2. Temperate cyclones
3. Extra-Tropical cyclones.

IV. Distinguish between the following.

Question 1.
Weather and climate.
Answer:

S.No.	Weather	Climate
(i)	Weather is the study of atmospheric conditions for a short duration over small areas.	It is the study of the average weather condition observed over a long period of time for a larger area.
(ii)	The weather changes very often; hour to hour and day today.	Climate is more (or) less permanent and remains the same always.
(iii)	The study of weather is called meteorology.	The study of climate is called climatology.

Question 2.
Land breeze and sea breeze.
Answer:

S.No.	Land Breeze	Sea Breeze
(i)	During the night the land cools more rapidly than the ocean. Cool air sinks and forms high pressure.	During the day the landmasses get heated more rapidly than the oceans.
(ii)	The wind that blows from land to sea during the night is called a land breeze.	Heated air ascends and this causes low pressure on the adjoining ocean, therefore the wind blows from the ocean to land in the afternoon. This is called a sea breeze.

Question 3.
Windward side and Leeward side.
Answer:

S.No.	Windward side	Leeward side
(i)	The windward side of a mountain which faces the prevailing wind.	The Leeward side of the mountain is the side sheltered from the wind.
(ii)	It receives heavy rainfall.	It receives very less rainfall.

Question 4.
Tropical cyclone and Temperate cyclones
Answer:

S.No.	Tropical cyclones	Temperate cyclones
(i)	Tropical cyclone develops in the Intertropical convergent zone. They are formed due to the differential heating of land & Sea.	Temperate cyclones are formed along a front, where hot and cold air masses meet.
(ii)	They often cause heavy loss of life and properly on the coasts and become weak after reaching the landmasses.	Temperate cyclones do not become weak like Tropical cyclones on reaching the land.
(iii)	Tropical cyclones are known as ‘cyclones’ in the Indian ocean.	Temperate cyclones are called western disturbances in India.

V. Give reasons.

Question 1.
Cyclones cause huge loss of life and property.
Answer:

1. A Tropical cyclone is a rapidly rotating storm system.
2. It is characterised by a low pressure center, a closed low level atmospheric circulation, strong winds and a spiral arrangement of thunderstorms, that produce heavy rain.
3. Very strong winds many damage installations, dwellings, communication systems, trees etc.
4. Therefore, it results in loss of life and property.
5. Heavy prolonged rains due to cyclones may cause river floods and submergence of low-lying areas of rain, causing loss of life and property.

Question 2.
Cloudy days are warmer than cloudless days.
Answer:
On a cloudy day some energy from the sun gets into the atmosphere through the clouds but can’t get out again, when this happens the heat builds up during the day, so it gets warmer outside.

Question 3.
Fog is dangerous for traffic.
Answer:

1. Fog is a thick cloud of tiny water droplets suspended in the atmosphere at or near the earth’s surface.
2. It obscures or restricts visibility to a greater extent than mist.
3. It strictly reduces visibility to below 1 km.
4. Many lives are lost each year worldwide from accidents involving fog conditions on the highways, including multiple – vehicle collisions.
5. The aviation travel industry is affected by the severity of fog conditions.

Question 4.
Convectional rainfall is also called 4 O’clock rain.
Answer:

1. The convectional rainfall occurs regularly in the equatorial region in the evenings.
2. The ascending moist air cools, condenses, and results in convectional rainfall. So it is called 4 O’clock rainfall.

Question 5.
Polar Easterlies are cold and dry. Why it is so?
Answer:

1. The polar easterlies are the dry, cold prevailing winds that blow from the high-pressure areas of the polar highs at the North and South poles towards low-pressure areas within the westerlies at high latitudes when air moves near the poles, cold temperatures shrink the air.
2. These are weak winds flowing from the Northeast direction in the Northern Hemisphere and South east direction in the Southern Hemisphere.

VI. Paragraph Questions.

Question 1.
Write a paragraph about the structure of the atmosphere.
Answer:
The blanket of air that surrounds the Earth is called the atmosphere. The five atmospheric layers are Troposphere, Stratosphere, Mesosphere, Thermosphere and Exosphere.
Troposphere: The lowest layer of the atmosphere is the troposphere. The Greek word ‘tropos’ means ‘turn’ or change. The layer extends up to 8 kms at the poles and up to 18 kms at the Equator. The temperature decreases with increasing height. Almost all weather phenomenon take place in this layer. Hence it is called weather making layer. The upper limit of the troposphere is called as tropopause.

Stratosphere: Stratosphere lies above the troposphere. It extends to a height of about 50 km above earth surface. Since this layer is a concentration of ozone molecules, it is also referred as ozonosphere. The temperature increases with increase in height in this layer. Large jet planes normally fly here. The upper limit of the stratosphere is called as stratopause. Mesosphere: Mesosphere extends between 50km and 80km. The temperature increases with increasing height. Radio waves transmitted from earth are reflected back to earth from this layer. Most of the meteors nearing the earth, get burned here. The uppermost limit of the mesosphere is the mesopause.

Thermosphere: Thermosphere exists above the mesosphere. It extends to about 600 km. The composition of gases in the lower thermosphere is more or less uniform, hence it is called ‘‘Homosphere”. The upper portion of the thermosphere has uneven composition of gases and hence it is referred as “Heterosphere”. Here the temperature increases with increasing height. Ionosphere is a layer of the thermosphere that contains Ions and free electrons.

Exosphere: The uppermost layer of the atmosphere is called exosphere. This layer is extremely rarefied with gases and gradually merges with the outer space. This zone is characterized by aurora Australis and aurora borealis.

Question 2.
Explain the different types of permanent winds.
Answer:
Westerlies are the permanent Winds that blow from the tropical high pressure belt to the sub polar low pressure belt in both the hemispheres. They blow from South West to North East . in the northern hemisphere and North West to South East in the southern hemisphere. The velocity of westerlies become so vigorous and fast to be called Roaring Forties at 40°, Furious Fifties at 50° and Screaming Sixties at 60° latitudes.

Question 3.
How are clouds classified? Explain them.
Answer:
According to their height, clouds are classified into the following types

• High clouds (6 – 20 km Height)
• Middle clouds (2.5 km – 6 km Height)
• Low clouds (ground surface to 25 km height)

These major types of clouds are further divided into different types on the basis of shape and structure.

1. High clouds
   • Cirrus: Detached clouds in the form of white delicate fibrous silky filaments formed at the high sky (8000 meters to 12000 meters) are called Cirrus clouds. These clouds are dry and do not give rainfall.
   • Cirrocumulus: White patched, sheet or layer like clouds composed of ice crystals. Cirrostratus: Smooth milky transparent whitish clouds composed of tiny ice crystals.
2. Middle clouds
   • Alto-stratus: Thin sheets of grey or blue coloured clouds in uniform appearance, consisting of frozen water droplets.
   • Alto-cumulus: clouds fitted closely together in parallel bands, called ‘Sheep clouds’ or woolpack clouds.
   • Nimbo stratus: These are clouds of dark colour very close to the ground surface associated with rain, snow or sleet.
3. Low clouds
   • Strato-cumulus: Grey or whitish layer of non-fibrous low clouds found in rounded patches at a height of 2500 to 3000 meters, associated with fair or clear weather.
   • Stratus: Dense, low lying fog-like clouds associated with rain or snow.
   • Cumulus: Dome-shaped with a flat base often resembling a cauliflower, associated with fair weather.
   • Cumulo-nimbus: Fluffy thick towering thunderstorm cloud capable of producing heavy rain, snow, hailstorm or tornadoes.

Question 4.
How are cyclones formed? How are they classified?
Answer:
The term cyclone is a Greek word meaning “coil of a snake”. Cyclones are centres of low pressure where winds from the surrounding high-pressure area converge towards the centre in a spiral form. Due to the rotation of the earth, the cyclonic winds in the northern hemisphere move in anti-clockwise direction, whereas they move in a clockwise direction in the southern hemisphere.
Cyclones can be classified into

Tropical cyclones, Temperate cyclones and Extratropical cyclones. Tropical cyclones: Tropical cyclones develop in the Intertropical convergence zone [ITCZ], They are formed due to the differential heating of land and sea.
Tropical cyclones are known as ‘cyclones’ in Indian ocean, ‘typhoons’ in the western pacific ocean, ‘hurricanes’ in the Atlantic and eastern Pacific ocean, ‘baguios’ in Phillipines and ‘willy willy’ in Australia. Tropical cyclones often cause heavy .loss of life and property on the coasts and become weak after reaching the landmasses.

Temperate cyclones: Temperate cyclones are formed along a front where hot and cold air masses meet in mid-latitudes between 35° and 65°N and S. Temperate cyclones do not become weak like the tropical cyclones on reaching the land. Temperate cyclone commonly occurs over the North Atlantic Ocean, northwest Europe, Mediterranean basin. Mediterranean basin’s temperate cyclones extend up to Russia and India in winter. In India, it is called the western disturbances.

Extratropical cyclones: Extratropical cyclones occur in the latitudes between 30° and 60° in both hemispheres. They are also called mid-latitude cyclones. They collect energy from temperature differences which are found in higher latitudes. Extratropical cyclones produce mild showers to heavy gales, thunderstorms, blizzards, and tornadoes.

Question 5.
Explain the different forms of precipitation.
Answer:
Precipitation
Falling down of condensed water vapour in different forms is called Precipitation. When the dew point is reached in the cloud water droplets become saturated and start to fall. Hence, they fall on the earth as precipitation.
The climatic conditions/ factors influencing the forms of precipitation mainly are:

• Temperature.
• Altitude
• Cloud type
• Atmospheric conditions.
• Precipitation process.

The main forms of precipitation include drizzle, rain, sleet, snow, hail, etc.
Drizzle: The falling of numerous uniform minute droplets of water with a diameter of less than 0. 5 is called a drizzle from low clouds. Sometimes drizzles are combined with fog and hence reduce visibility.

Rain: Rain is the most widespread and important form of precipitation in places having temperatures above the freezing point. It occurs only when there is abundant moisture in the air. The diameter of a raindrop is more than 5 mm.

Sleet: Sleet refers to precipitation, in the form of pellets made up of transparent and translucent ice. This precipitation is a mixture of snow and rain.

Snow: Snow is formed when condensation occurs below the freezing point. It is the precipitation of opaque and semi-opaque ice crystals. When these ice crystals collide and stick together, it becomes snowflakes.

Hails: Hails are chunks of ice (greater than 2 cm in diameter) falling from the sky, during a rainstorm or thunderstorm.
Hailstones are a form of solid precipitation where small pieces of ice fall downwards. These are destructive and dreaded forms of solid precipitation because they destroy agricultural crops and human lives.

VII. Activity:

1. Preparing chart of clouds at various atmospheric levels. – Individual Activity.
2. Collecting proverbs clouds and rain-related proverbs. – Individual Activity.
3. Poem on ‘clouds’ and ‘rain’. – Individual Activity.
4. Report writing observes the clouds for a week. Write your report about the shape and colours of the clouds. – Group Activity.
5. Working models (a) Rain Gauge (b) Wind vane – Group Activity.
   • The teacher takes initiative to complete the following activities.
   • The students get the assistance of the teacher to complete the given task.
6. Preparing a bar diagram:
   (a) Collect the data of the temperature of Kanyakumari, Delhi, Allahabad, and Itanagar for a day.
   (b) Also collect the data of rainfall received by Jaisalmer (Rajasthan), Mawsynram (Meghalaya), Nagapattinam, Coimbatore for a day. – Group Activity.
7. Become a budding Meteorologist:
   Record the local weather condition of your place for a week. – Group Activity.
   

Answer:
You can do this activity in groups under the guidance of your teacher.

In-text HOTs Questions

Question 1.
Why is Troposphere called weather making layer?
Answer:
The troposphere is the lowest layer of the atmosphere. It is also known as the weather-making zone because all physical processes of weather, like wind, clouds, storms, rainfall, mist, fog, and hail, occur here.

Atmosphere Additional Questions

I. Choose the correct answer.

Question 1.
This is a permanent gas in the atmosphere.
(a) Nitrogen
(b) Argon
(c) Methane
(d) Helium
Answer:
(a) Nitrogen

Question 2.
This gas helps in protecting the earth from radiation.
(a) Hydrogen
(b) Nitrogen
(c) Ozone
(d) CO₂
Answer:
(c) Ozone

Question 3.
The uppermost layer of the atmosphere is …………….
(a) Stratosphere
(b) Mesosphere
(c) Exosphere
(d) Thermosphere
Answer:
(c) Exosphere

Question 4.
This precipitation is a mixture of snow and rain.
(a) Sleet
(b) Snow
(c) Hail
(d) Hailstones
Answer:
(a) Sleet

Question 5.
The humidity of the atmosphere is measured by the wet and dry bulb thermometer called ………….
(a) Anemometer
(b) Thermometer
(c) Hygrometer
(d) Barometer
Answer:
(c) Hygrometer

Question 6.
This is one of the most feared weather phenomena.
(a) Snow
(b) Hailstones
(c) Sleet
(d) Hails
Answer:
(b) Hailstones

Question 7.
Tropical cyclones in India is known as ……………
(a) Baguio’s
(b) willy willy
(c) hurricanes
(d) Cyclones
Answer:
(d) Cyclones

Question 8.
The wind blowing from the east is ……………
(a) Planetary winds
(b) Easterly winds
(c) Variable winds
(d) Local winds
Answer:
(b) Easterly winds

Question 9.
This is the wettest place in India.
(a) Mawsynram
(b) the Western Ghats
(c) Shillong
(d) Pune
Answer:
(a) Mawsynram

Question 10.
This is the earth’s magnetic belt ………………
(a) Thermosphere
(b) Stratosphere
(c) Mesosphere
(d) Magnetosphere
Answer:
(d) Magnetosphere

II. Match the following.
(a)

Answer:
(a)
1. (e)
2. (a)
3. (b)
4. (d)
5. (c)

(b)

Answer:
(b)
1. (d)
2. (c)
3. (a)
4. (e)
5. (b)

III. Answer the following questions briefly.

Question 1.
Who discovered Nitrogen in the Atmosphere? When?
Answer:
In 1772 CE Daniel Rutherford discovered Nitrogen in the atmosphere.

Question 2.
What are Auroras?
Answer:
Auroras are cosmic glowing lights produced by a stream of electrons discharged from the Sun’s surface due to magnetic storms that are seen as unique multicolored fireworks hanging in the polar sky during midnight.

Question 3.
What are mountain barriers?
Answer:

• The location of the mountains influences the climate of a place.
• The mountain chains act as a natural barrier for the wind.
• Sometimes they prevent the entry of cold winds into the country (or) the escape of monsoon winds, thus having a great influence over the climate.

Question 4.
What happens to atmospheric pressure with altitude?
Answer:

• Air pressure decreases with altitude.
• The air molecules became scattered and more widely spaced at higher altitudes.
• The air pressure develops by 34 millibars per 300 meters increase in height.

Question 5.
What do you call the winds of a particular area?
Answer:

• The winds that are blown in a particular locality for a short period of time are called the local winds.
• The effects of these local winds are experienced only in that particular area.

Question 6.
Define the terms (a) Absolute humidity (b) Relative humidity.
Answer:
Absolute humidity: The amount of water vapour in the atmosphere is called Absolute Humidity.
Relative Humidity: The ratio between the amount of water vapour in the atmosphere and the amount of water vapour it can hold is Relative humidity.

IV. Distinguish between the following.

Question 1.
Conduction and Convection.
Answer:

Conduction	Convection
Conduction is the transfer of heat from a hot body to a cold body through contact.	Convection is the transfer of heat by movement or circulation of air in a mass.

Question 2.
Isobar and Isotherm.
Answer:

Isobar	Isotherm
An Isobar is an imaginary line drawn through places having equal atmospheric pressure reduced to sea level.	An imaginary line on a map connecting points having the same temperature

V. Give reasons.

Question 1.
Thermosphere is also referred to as “Heterosphere”.
Answer:
The upper portion of the Thermosphere has an uneven composition of gases and hence it is referred as “Heterosphere”.

Question 2.
The wind blows from ocean to land in the afternoon. Why?
Answer:

1. During the day the land masses get heated more rapidly than the oceans.
2. Heated air ascends and causes low pressure on the adjoining ocean.
3. Therefore the wind blows from ocean to land in the afternoon.

Question 3.
The subtropical high pressure are called “horse latitudes”. Why?
Answer:

1. With little water and food left for humans, sailors used to throw the horses into the sea in order to make the vessels lighter.
2. Henceforth these belts (or) latitudes are called “horse latitudes”.

Question 4.
“Water droplets fall on the earth as precipitation”. Why?
Answer:

1. When the dew point is reached in the cloud, water droplets become saturated and start to fall.
2. Hence they fall on the earth as precipitation.

VI. Paragraph questions.

Question 1.
Describe the “composition of the atmosphere”.
Answer:
(i) Atmosphere is a mixture of gases, water vapour and dust particles in different proportions.

(ii) Nitrogen (78%) and Oxygen (21%) are permanent gases of the atmosphere. They constitute 99% of the total composition and their percentages always remain the same without any change.

(iii) The remaining one percentage is occupied by Argon (0.93%), Carbon-di-oxide, (0.03%), Neon (0.0018%), Helium (0.0005%), Ozone (0.00006%) and Hydrogen (0.00005%). Krypton, Xenon and Methane are also present in trace. Water vapour (0 – 0.4%) is also found in the atmosphere, which plays an important role in predicting weather phenomenon.

(iv) The other solid particles present in the atmosphere includes dust particles, salt particles, pollen grains, smoke, soot, volcanic ashes etc.,
(v) Oxygen is most important for living organisms.
(vi) CO₂ absorbs heat and keeps the atmosphere warm by insulation and radiation.
(vii) Nitrogen acts as a diluent and is chemically inactive.
(viii) Ozone helps in protecting the earth from radiation.
(ix) The solid particles in the atmosphere acts as nuclei on which water vapour condense to form precipitation.

Question 2.
How is the Orographic rainfall caused?
Answer:
Orographic rainfall, also called relief rainfall, is caused when air is forced to rise against a high mountain. The mountain barriers lying across the direction of air flow, force the moisture laden air rise along the mountain slope. This results in the cooling of the air, which leads to the formation of clouds and rain. This rainfall is called Orographic rainfall. The side of the ‘ mountain facing the wind is called the windward side and receives heavy rainfall. It is called the rainfed region. The other side of the mountain that does not face the wind is called the leeward side and receives less rainfall becomes rain shadow region.

VII. HOTs (Higher Order Thinking skills) Questions

Question 1.
Why is Troposphere called as weather making layer?
Answer:
‘Tropos’ means ‘turn’ (or) change. Almost all weather phenomenon takes place in this layer. Hence Troposphere is called as weather making layer.

Question 2.
Cuddalore and Nagapattinam are always affected by cyclones. Why?
Answer:

1. Coastal zone is exposed to natural forces including cyclones and Tsunamis.
2. Cuddalore and Nagapattinam are situated on the Sea-Shore.
3. Cuddalore and Nagapattinam are vulnerable to storms.
4. During Summer Bay of Bengal subject to intense heat cause to raise the humid and unstable air masses that produce cyclone.

You can Download Samacheer Kalvi 11th Maths Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 11th Maths Solutions Chapter 1 Sets Ex 1.2

Question 1.
Discuss the following relations for reflexivity, symmetricity and transitivity:

(i) The relation R defined on the set of all positive integers by “mRn if m divides n”.
Solution:
Let Z = {1, 2, 3, ……….}
R is a relation defined on the set of all positive integers by m R n if m divides n
R = { (m, n) : \(\frac{\mathrm{m}}{\mathrm{n}}\) for all m, n ∈ Z } n

(a) Reflexive:
m divides m for all m ∈ Z
∴ (m, m) ∈ R for all m ∈ Z
Hence R is reflexive

(b) Symmetric:
Let (m, n) ∈ R ⇒ m divides n
⇒ n = km for some integers k
But km need not divide m, ie. n need not divide m
∴ (n, m) ∉ R
Hence R is not symmetric.

(c) Transitive:
Let (m, n), (n, r) ∈ R
Then m divides n ⇒ n = km and
n divides r ⇒ r = k₁n
r = k₁(km) = (k₁k) m
m divides r
∴ (m, r) ∈ R
Hence R is transitive.

(ii) Let P denote the set of all straight lines in a plane. The relation R defined by “lRm if l is perpendicular to m”.
Solution:
P = {set of all straight lines in a plane}
lRm ⇒ l is perpendicular to m

(a) lRl ⇒ l is not perpendicular to l
⇒ It is not reflexive

(b) lRm ⇒ l is perpendicular to m
mRl ⇒ m is perpendicular to l
It is symmetric

(c) l perpendicular to m ⇒ m perpendicular to n ⇒ l is parallel to n It is not transitive

(iii) Let A be the set consisting of all the members of a family. The relation R defined by “aRb if a is not a sister of b”.
Solution:
Let F = Father,
M = Mother
G = Male child
H = Female child
A = { F, M, G, H }
The relation R is defined by
a R b if a is not a sister of b.
R = {(F, F), (F, M), (F, G), (F, H), (M, F), (M, M), (M, G), (M, H), (G, F), (G, M), (G, G), (G, H), (H, F), (H, M), (H, H)}

(a) Reflexive:
(F, F) , (M , M), (G, G), ( H, H ) ∈ R
∴ R is reflexive.

(b) Symmetric:
For (G, H) ∈ R, we have (H, G) ∉ R
∴ R is not symmetric.

(c) Transitive:
Suppose in a family if we take mother M , male child-G and female child-H.
H is not a sister of M ⇒ HRM, (H, M) ∈ R
M is not a sister of G ⇒ MRG, (M, G) ∈ R
But H is a sister of G ⇒ HRG, (H, G) ∉ R
Thus, for (H, M), (M, G) ∈ R
we have (H, G) ∉ R
∴ R is transitive.

(iv) Let A be the set consisting of all the female members of a family. The relation R
defined by “aRb if a is not a sister of b”.
Solution:
A = {set of all female members of a family}

(a) aRa ⇒ a is a sister of a
It is reflexive

(b) aRb ⇒ a is a sister of b
bRa ⇒ b is the sister of a
⇒ It is symmetric

(c) aRb ⇒ a is a sister of b bRc ⇒ b is a sister of c aRc ⇒ a can be the sister of c It is not transitive.

(v) On the set of natural numbers the relation R defined by “xRy if x + 2y = 1”.
Solution:
x + 2y = 1 for x, y ∈ N
There is no x , y ∈ N satisfying x + 2y = 1
∴ The relation R is an empty relation.
An empty relation is symmetric and transitive.
∴ R is symmetric and transitive.
R is not reflexive

Question 2.
Let X = {a, b, c, d} and R = {(a, a), {b, b), (a, c)}. Write down the minimum number
of ordered pairs to be included to R to make it
(i) reflexive
(ii) symmetric
(iii) transitive
(iv) equivalence
Solution:
X = {a, b, c, d}
R = {(a, a), (b, b), (a, c)}
(i) To make R reflexive we need to include (c, c) and (d, d)
(ii) To make R symmetric we need to include (c, a)
(iii) R is transitive
(iv) To make R reflexive we need to include (c, c)
To make R symmetric we need to include (c, c) and (c, a) for transitive
∴ The relation now becomes
R = {(a, a), (b, b), (a, c), (c, c), (c, a)}
∴ R is equivalence relation.

Question 3.
Let A = {a, b, c} and R = {(a, a), (b, b), (a, c)}. Write down the minimum number of ordered pairs to be included to R to make it
(i) reflexive
(ii) symmetric
(iii) transitive
(iv) equivalence
Solution:
Given A = {a, b, c }
R = { (a, a), (b, b),(a, c) }
(i) The minimum ordered pair to be included to R in order to make it reflexive is (c, c).
(ii) The minimum ordered pair to be included to R in order to make it symmetrical is (c, a).
(iii) R is transitive. We need not add any pair.
(iv) After including the ordered pairs (c, c),(c, a) to R the new relation becomes
R₁ = { (a, a), (b, b), (c, c) , (a, c) , (c, a) }
R₁ is reflexive symmetric and transitive.
∴ R₁ is an equivalence relation.

Question 4.
Let P be the set of all triangles in a plane and R be the relation defined on P as aRb if a is
similar to b. Prove that R is an equivalence relation.
Solution:
P = {set of all triangles in a plane}
aRb ⇒ a similar to b

(a) aRa ⇒ every triangle is similar to itself
∴ aRa is reflexive

(b) aRb ⇒ if a is similar to b ⇒ b is also similar to a.
⇒ It is symmetric

(c) aRb ⇒ bRc ⇒ aRc
a is similar to b and b is similar to c
⇒ a is similar to a
⇒ It is transitive
∴ R is an equivalence relation

Question 5.
On the set of natural numbers let R be the relation defined by aRb if 2a + 3b = 30. Write down the relation by listing all the pairs. Check whether it is
(i) reflexive
(ii) symmetric
(iii) transitive
(iv) equivalence
Solution:
N = {set of natural numbers}
R ={(3, 8), (6, 6), (9, 4), (12, 2)}

(a) (3, 3) ∉ R ⇒ R is not reflexive
2a + 3b = 30
3b = 30 – 2a
b = \(\frac{30-2 a}{3}\)

(b) (3, 8) ∈ R(8, 3) ∉ R
⇒ R is not symmetric

(c) (a, b) (b, c) ∉ R ⇒ R is transitive
∴ It is not an equivalence relation.

Question 6.
Prove that the relation “friendship” is not an equivalence relation on the set of all people in Chennai.
Solution:
If a is a friend of b and b is a friend of c, then a need not be a friend of c.
a R b and b R c does not imply a R c.
∴ R is not transitive.
∴ The relation is not an equivalence relation.

Question 7.
On the set of natural numbers let R be the relation defined by aRb if a + b ≤ 6. Write down the relation by listing all the pairs. Check whether it is
(i) reflexive
(ii) symmetric
(iii) transitive
(iv) equivalence
Solution:
Set of all natural numbers aRb if a + b ≤ 6
R= {(1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (2, 1), (2, 2), (2, 3), (2, 4), (3, 1), (3, 2), (3, 3), (4, 1), (4, 2), (5, 1)}
(i) (5, 1) ∈ R but(5, 5) ∉ R
It is not reflexive

(ii) aRb ⇒ bRa ⇒ It is symmetric

(iii) (4, 2), (2, 3) ∈ R ⇒ (4, 3) ∉ R
∴ It is not transitive

(iv) ∴ It is not an equivalence relation

Question 8.
Let A = {a, b, c}. What is the equivalence relation of smallest cardinality on A? What is the equivalence relation of largest cardinality on A?
Solution:
A = { a, b, c }
Let R₁ = { (a, a),(b, b),(c, c) }
Clearly, R₁ is reflexive, symmetric, and transitive.
Thus R₁ is the equivalence relation on A of smallest cardinality, n (R₁) = 3
Let R₂ = { (a, a), (b, b), (c, c), (a, b), (b, a), (b, c), (c, b), (c, a), (a, c)}

(i) Reflexive:
(a, a) , (b, b) , (c, c) ∈ R
∴ R₂ is reflexive.

(ii) Symmetric:
(a , b) ∈ R₂ we have (b, a) ∈ R₂
(b , c) ∈ R₂ we have (c, b) ∈ R₂
(c , a) ∈ R₂ we have (a, c) ∈ R₂
∴ R₂ is symmetric.

(iii) Transitive:
(a, b), (b, c) ∈ R₂ ⇒ (a, c) ∈ R₂
(b, c), (c, a) ∈ R₂ ⇒ (b, a) ∈ R₂
(c, a) , (a, b) ∈ R₂ ⇒ (c, b) ∈ R₂
∴ R₂ is transitive and R₂ is an equivalence relation of largest cardinality.
n (R₂) = 9

Question 9.
In the set Z of integers, define mRn if m – n is divisible by 7. Prove that R is an equivalence relation.
Solution:
mRn if m – n is divisible by 7
(a) mRm = m – m = 0
0 is divisible by 7
∴ It is reflexive

(b) mRn = {m – n) is divisible by 7
nRm = (n – m) = – {m – n) is also divisible by 7
It is symmetric

It is transitive
mRn if m – n is divisible by 7
∴ R is an equivalence relation.

Samacheer Kalvi 11th Maths Solutions Chapter 1 Sets Ex 1.2 Additional Questions

Question 1.
Find the range of the function.
f = {(1, x), (1, y), (2, x), (2, y), (3, z)}
Solution:
The range of the function is {x, y, z}.

Question 2.
For n, m ∈ N, It means that it is a factor of n & m. Then find whether the given relation is an equivalence relation.
Solution:
Since n is a factor of n. So the relation is reflexive.
When n is a factor of m (where m ≠ n) then m cannot be a factor of n.
So the relation is not symmetric when n is a factor of m and m is a factor of p then n will be a factor of p. So the given relation is transitive. So it is not an equivalence relation.

Question 3.
Verify whether the relation “is greater than” is an equivalence relation.
Solution:
You can do it yourself.