Class 7 Geography Chapter 3 – Our Changing Earth (NCERT / JKBOSE) Question Answers
Our Changing Earth is an important chapter in Class 7 Geography that explains how natural processes constantly shape and reshape the Earth’s surface. Students will learn about earthquakes, volcanoes, weathering, erosion, and other processes in a simple and easy-to-understand way.
In this post, you will find complete Question–Answer solutions for JKBOSE/NCERT Chapter 3, prepared in clear language for easy learning and quick memorization. The content is well-structured, exam-oriented, and ideal for revision, helping students strengthen their concepts and perform confidently in exams. Students can read online or download free quality notes to make learning Geography interesting, effective, and stress-free.
1. Answer the following questions
(i) Why do the plates move?
The plates move due to the movement of the molten magma or heat inside the earth. In other words, plates move due to convection currents in the mantle caused by Earth’s internal heat.
(ii) What are exogenic and endogenic forces?
Exogenic forces are the forces that work on the surface of the earth. They include weathering, erosion, and deposition caused by wind, water, ice, and waves. These forces wear down landforms.
Endogenic forces are the forces that act in the interior of the earth. They cause movements like earthquakes, volcanoes, folding, and faulting, which build mountains and plateaus.
(iii) What is erosion?
Erosion is the process by which soil and rock are worn away and carried from one place to another by natural agents like water, wind, ice, and waves. This process of erosion and deposition creates different landforms on the surface of the earth.
(iv) How are flood plains formed?
As the river overflows its banks, it floods the neighbouring areas. Layers of fine soil and other material called sediments get deposited along its banks. This leads to the formation of flat and fertile flood plains.
(v) What are sand dunes?
Sand dunes are heaps of sand formed by wind deposition, mainly in deserts. When the wind blows, it lifts and transports sand from one place to another. When it stops blowing, the sand falls and gets deposited in low hill-like structures called sand dunes.
(vi) How are beaches formed?
Beaches are formed when sea waves deposit sediments along the coast.
(vii) What are ox-bow lakes?
An ox-bow lake is a crescent-shaped lake. It is formed when a river enters the plains and twists and turns forming large bends called meanders. Over time, the meander loops get cut off from the river and form cut-off lakes called ox-bow lakes.
2. Tick the correct answer
(i) Which is not an erosional feature of sea waves?
(a) Cliff
(b) Beach
(c) Sea cave
Answer: b) Beach
(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) Ox-bow lakes are found in:
(a) Glaciers
(b) River valleys
(c) Deserts
Answer: b) River valleys
3. Match the following
(Section provided for practice)
4. Give reasons
(i) Some rocks have a shape of a mushroom.
Rocks get a mushroom shape due to wind erosion. The wind erodes the lower section of the rock more than the upper part, creating a narrow base and wider top.
(ii) Flood plains are very fertile.
Flood plains are very fertile because rivers deposit fine, mineral-rich alluvium during floods, making the soil rich and suitable for agriculture.
(iii) Sea caves are turned into stacks.
Sea caves turn into stacks due to the constant action of sea waves that erode and break the rocks.
(iv) Buildings collapse due to earthquakes.
Buildings collapse when they cannot resist the powerful vibrations produced during an earthquake.
Reasons include:
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Strong shaking weakens the foundation
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Poorly constructed buildings cannot withstand vibrations
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Soft soil may amplify the shaking
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Heavy roofs and weak materials make structures unstable
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