9th Social Science - Book Back Answers - Geography Unit 2

9th - Social Science - Book Back Answers - Geography Unit 2 - English Medium

Tamil Nadu Board 9th Standard Social Science - Geography Unit 2: Book Back Answers and Solutions

This post covers the book back answers and solutions for Unit 2 – Geography from the Tamil Nadu State Board 9th Standard Social Science textbook. These detailed answers have been carefully prepared by our expert teachers at KalviTips.com.

We have explained each answer in a simple, easy-to-understand format, highlighting important points step by step under the relevant subtopics. Students are advised to read and memorize these subtopics thoroughly. Once you understand the main concepts, you’ll be able to connect other related points with real-life examples and confidently present them in your tests and exams.

By going through this material, you’ll gain a strong understanding of Geography Unit 2 along with the corresponding book back questions and answers (PDF format).

Question Types Covered:

1 Mark Questions: Choose the correct answer, Fill in the blanks, Identify the correct statement, Match the following
2 Mark Questions: Answer briefly
3, 4, and 5 Mark Questions: Answer in detail

All answers are presented in a clear and student-friendly manner, focusing on key points to help you score full marks.

All the best, Class 9 students! Prepare well and aim for top scores. Thank you!

Topic: Unit 2. LITHOSPHERE - II EXOGENETIC PROCESSES

I. Choose the correct Answer

Question 1.
The disintegration or decomposition of rocks is generally called as ___________
(a) weathering
(b) erosion
(c) transportation
(d) deposition
Answer Key:
(a) weathering

Question 2.
The process of the levelling up of land by means of natural agents.
(a) aggradation
(b) degradation
(c) gradation
(d) none
Answer Key:
(c) gradation

Question 3.
_______ is seen in the lower course of the river.
(a) Rapids
(b) Alluvial fan
(c) Delta
(d) Gorges
Answer Key:
(c) Delta

Question 4.
Karst topography is formed due to the action of _________
(a) Glacier
(b) Wind
(c) Sea waves
(d) Ground Water
Answer Key:
(d) Ground Water

Question 5.
Which one of the following is not a depositional feature of a glacier?
(a) cirque
(b) Moraines
(c) Drumlins
(d) Eskers
Answer Key:
(a) cirque

Question 6.
Deposits of fine silt blown by wind is called as ___________
(a) Loess
(b) Barchans
(c) Hamada
(d) Ripples
Answer Key:
(a) Loess

Question 7.
Stacks are formed by __________.
(a) Wave erosion
(b) River erosion
(c) Glacial erosion
(d) Wind deposion
Answer Key:
(a) Wave erosion

Question 8.
______ erosion is responsible for the formation of cirque
(a) wind
(b) glacial
(c) river
(d) underground water
Answer Key:
(b) glacial

II. Match the following

1. Distributaries        – (i) glacial action
2. Mushroom rock      – (ii) action of sea wave
3. Eskers                      – (iii) Lower course of river
4. Stalactites               – (iv) Aeolian process
5. Cliff                      – (v) karst topography

Answer Key:

1. Distributaries        – (iii) Lower course of river
2. Mushroom rock    – (iv) Aeolian process
3. Eskers                     – (i) glacial action
4. Stalactites            – (v) karst topography
5. Cliff                         – (ii) action of sea wave

III. Consider the given statement

Question 1.
(i) ‘I’ Shaped valley is an erosional feature of the river
(ii) ‘U’ Shaped valley is an erosional feature of the glacier
(iii) ‘V’ Shaped valley is an erosional feature of the glacier
(a) (i), (ii) & (iii) are right
(b) (i) & (ii) are right
(c) (i) & (iii) are right
(d) only (i) is right
Answer Key:
(ii) is correct

Question 2.
Statement I: Running water is an important agent of gradation
Statement II: The work of the river depends on the slope of land on which it flows
(a) Statement I is false II is true
(b) Statement I and II are false
(c) Statement I is true II is false
(d) Statement I and II are true
Answer Key:
(d) Statement I and II are true

Question 3.
Statement: Limestone regions have less underground water.
Reason: Water does not percolate through limestone.
(a) The statement is right, reason is wrong.
(b) The statement is wrong, Reason is right.
(c) The statement and reason are wrong.
(d) The statement and reason are right.
Answer Key:
(c) The statement and reason are wrong.

IV. Distinguish Between

Distinguish between:

1. PHYSICAL WEATHERING	CHEMICAL WEATHERING
* It is the break down of rocks due to action of physical force. * The agents of physical weathering are constant freezing and excess heating.	* It is the break down of rocks due to chemical reactions. * The agents of chemical weathering are oxidation,Carbonation, solution and hydration.
2. DELTA	ESTUARY
* Delta is formed where the river lying area formed its mouth. * It's shape of deposition is triangular. * Ex., Cauvery delta.	* Estuary is formed where the river meets the sea. * There is no deposition. * Ex., Narmatha and Tapti.
3. STALACTITE	STALAGMITE
* When the calcite hangs from the ceiling stalactite are formed. * It hangs from ceiling of a cave.	When the calcite rises upward like a pillar stalagmites are formed. It grows from the cave's floor.
4. LONGITUDINAL	TRANSVERSE SAD DUNES
* Longitudinal dunes are long narrow ridges of sand. * They are formed by extend in a direction parallel to the prevailing winds.	* Transverse dunes are asymmetrical in shape. * They are formed by alternate slow and fast winds that blow from the same direction.
5. INSELBERGS	YARDANGS
* These hard rocks like igneous rocks are more resistant to wind action. * These are seen like island mountains.	* In arid regions these rocks have hard and soft layers arranged vertically. * These are seen irregular crests.
6. SPIT	BAR
* A spit is a ridge attached to the land on one end and terminating in open water on the other end. * Spits are common at the mouth of estuaries.	* A Bar is an elongated deposit of sand, shingle or mud found in the sea. * Bars are almost parallel to the shoreline.

V. Answer the following briefly

1. Define weathering.

Weathering is the disintegration and decomposition of materials of the earth's crust by their exposure to atmosphere.

2. What do you mean by biological weathering?

Biological weathering occurs due to penetration of plants, animals and some human activities.

3. Mention the three courses of a river with any two land forms associated to each course.

The upper course - "V shaped valleys, gorges.
The middle course - Alluvial fans, food plains.
The lower course - Deltas, estuaries.

4. What are ox - bow lakers?

Meanders in due course of time become almost a complete circle with narrow necks.
This in turn gets connected forms a lake.

5. How does a sea cave differ from a sea arch?

When two caves approach one another from either side of a headland and unite, they form an arch.

6. List out any four karst topographical areas found in India.

Guptadham caves - Western Bihar.
Robert caves - Uttarakhand.
Pandav caves - Madhya Pradesh.
Borra caves - Andhra Pradesh.

7.What do you mean by a hanging valley?

These are valleys eroded by tributary glacier and that hangs over the main valley.

8. Define: a) Moraine b) Drumlin c) Esker

Moraine:

Landforms formed by the glacial deposits of valley or continental glaciers are termed as moraines.

Drumlin:

Drumlins are deposits of glacial moraines that resemble giant inverted teaspoons or half cut eggs.

Esker:

Long narrow ridges composed of boulders gravel and sand deposited by streams of melting water which run parallel to a glacier are called eskers.

9. Mention the various features formed by wind erosion.

Mushroom rocks
Inselbergs
Yardangs

10. What are wave cut platforms?

Flat surface found at the foot of the sea cliffs are called as wave cut platforms.

VI. Answer all the questions given under each caption

1. Write a note on weathering classify and explain.

Weathering is the disintegration and decomposition of materials of the earth' s crust by their exposure to atmosphere.

There are three types of weathering

Physical weathering
Chemical weathering
Biological weathering

Physical weathering:

It is the breakdown of rocks due to action of physical force. Ex., Heat and Cold.

Chemical weathering:

It is the breakdown of rocks due to chemical reactions. Ex., Oxidation, Carbonation.

Biological weathering:

Biological weathering occurs due to penetration of plants, animals and some human activities.

2. Explain the erosional landforms formed by underground water.

Erosional landforms of underground water are:

Terra Rossa
Lappies
Sinkhole
Caves and Caverns

Terra Rossa:

Deposition of red clay soil on the surface of the Earth is due to the dissolution of limestone content in rocks is called terra rossa.

Lappies:

When the joins of Limestone rocks are corrugated by ground water, long furrows are formed and these are called Lappies.

Sinkhole:

A funnel shaped depressions formed due to dissolution of limestone rocks is called Sinkholes.

Caves and Cavers:

Caves are hollows that are formed by the dissolution of limestone rocks when Carbondioxide in air turns into Carbonic acid after its reaction with water.

3. What is glacier? Explain its types.

Glacier:

A Glacier is a large mass of ice that moves slowly over the land.

Types of Glacier:

Glaciers are divided into two types.
Continental Glacier.
Valley Glacier.

Continental Glacier:

Thick sheets of ice that covers vast area of a continent is called Continental Glacier.

Valley Glacier:

The glacier which takes its origin from a snow covered mountain range is known as a Valley Glacier.

4. Describe the depositional work of winds.

Depositional Landforms of wind

Deposition occurs when the speed of wind is reduced by the presence of obstacles like bushes, forests and rock structures. These sediments carried by wind get deposited on both the windward and leeward sides of these obstacles.

Some of the depositional landforms are

Sand dune
Barchan
Transverse Dunes
Longitudinal Dunes
Loess.