NCERT Solutions for Class 7 Social Science Geography Chapter 3 Our Changing Earth

Our Changing Earth Class 7 Questions and Answers Provided helps you to answer complex Questions too easily. You can use them while preparing for board exams and all of them are given by subject experts. Reading NCERT Solutions for Class 7 Social Science Geography Chapter 3 Our Changing Earth familiarizes you with the kind of questions appearing in the board exams. Students are advised to read these solutions on a regular basis to score well.

Our Changing Earth Class 7 Questions and Answers Geography Chapter 3

Make your learning experience enjoyable by preparing from the quick links available on this page. Use the Class 7 SST Geography Chapter 3 NCERT Solutions and get to know different concepts involved. All the Solutions are covered as per the latest syllabus guidelines. Knowing the NCERT Class 7 Geography Chapter 3 Questions and Answers helps students to attempt the exam with confidence.

Class 7 Geography Chapter 3 NCERT Textbook Questions and Answers

Question 1.
Answer the following questions.

(i) Why do the plates move?
(ii) What are exogenic and endogenic forces?
(iii) What is erosion?
(iv) How are flood plains formed?
(v) What are sand dunes?
(vi) How are beaches formed?
(vii) What are ox bow lakes?

Answer:
(i) Plates move because of the movement of the molten magma inside the earth.
(ii) Endogenic forces: The forces that act in the interior of the earth are called endogenic forces. Exogenic forces: The forces that work on the surface of the earth are called exogenic forces.
(iii) Erosion is the wearing away of the landscape by different agents like water, wind and ice.(iv) Layer of the fine soil and other material called sediments are deposited on the bank of river during the floods. Gradually, this leads to formation of plains.
(v) When the wind stops blowing, the sand falls and gets deposited in low hill like structures. These are called sand dunes.
(vi) Beaches are formed when the sea waves deposit sediments along the shores of the sea.(vii) When the meander loop cuts off from the river and forms a cut-offlake, also called an ox-bow lake.

NCERT Solutions for Class 7 Social Science Geography Chapter 3 Our Changing Earth

Question 2.
Tick the correct answer.
(i) Which is not an erosional feature of sea waves?
(a) Cliff
(b) Beach
(c) Sea cave
Answer:
(a) Cliff

(ii) The depositional feature of a glacier is:
(a) Flood plain
(b) Beach
(c) Moraine
Answer:
(c) Moraine

(iii) Which is caused by the sudden movements of the earth?
(a) Volcano
(b) Folding
(c) Flood plain
Answer:
(a) Volcano

(iv) Mushroom rocks are found in:
(a) Deserts
(b) River valleys
(c) Glaciers
Answer:
(a) Deserts

(v) Oxbow lakes are found in:
(a) Glaciers
(b) River valleys
(c) Deserts
Answer:
(b) River valleys

3. Match the following.

Column I Column II
1. Glacier (a) Sea shore
2. Meanders (b) River of ice
3. Beach (c) Rivers
4. Sand Dunes (d) Vibrations of earth
5. Waterfall (e) Hard bedrock
6. Earthquake (f) Deserts

Ans.
(i) (b)
(ii) (e)
(iii) (a)
(iv) (f)
(v) (c)
(vi) (d)

Question 4.
Give reasons.
(i) Some rocks have a shape of a mushroom.
(ii) Flood plains are very fertile.
(iii) Sea caves are turned into stacks.
(iv) Buildings collapse due to earthquakes.
Answer:

(i) Winds erode the lower section of the rock more than the upper part. Therefore, such rocks have narrower base and wider top which take the shape of a mushroom.

(ii) At times the river overflows its bank. This leads to the flooding of the neighbouring areas. As it floods, it deposits layers of fine soil and other material called sediments along its bank. This leads to the formation of a flat fertile floodplain.

(iii) Sea caves are turned into stacks, the reason is that sea waves continuously strike at the rocks and thus cracks are developed. Over time they become larger and wider. Thus, hollow like caves are formed on the rocks. They are called sea caves. As these cavities become bigger and bigger only the roof of the caves remain, thus forming sea arches. Further, erosion breaks the roof and only wall are left. These walls like features are called stacks and thus sea caves are turned into stacks.

(iv) The building collapses due to earthquake because when the Lithospheric plates move, the surface of the earth vibrates. Greatest damage is usually closest to the epicentre. An earthquake over 5.0 can cause damage from things falling. A 6.0 or more is considered very strong. The building may collapse due to the frequency over 5.0 on Richter scale. Apart from this, sometimes buildings are not constructed safe in view of the earthquakes. Hence, building collapses due to a low frequency of earthquakes.

NCERT Solutions for Class 7 Social Science Geography Chapter 3 Our Changing Earth

Question 5.
Observe the photographs given below. These are various features made by a river. Identify them and also tell whether they are erosional or depositional or landforms formed by both.
Answer:
NCERT Solutions for Class 7 Social Science Geography Chapter 3 Our Changing Earth 1
NCERT Solutions for Class 7 Social Science Geography Chapter 3 Our Changing Earth 2

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