Important Question Answers for the Class 9-Social Science Chapter 2- Landforms: Earth's Living Canvas ***************************** Very Short Answer Questions: ************************** 1. Define plate tectonics. Answer:- Plate tectonics is the theory that the Earth's lithosphere is divided into plates that move slowly over time. 2. Name the 3 main layers of the earth. Answer:- The 3 main layers are * Crust * Mental * Core 3. What is weathering? Answer:- Weathering is the breaking of rocks into smaller pieces at the same place. 4. What is erosion? Answer:- Erosion is the removal and transportation of weathered material from one place to another. 5. Name two agents of erosion. Answer:- * Rivers * Wind 6. What is a glacier? Answer:- A glacier is a large mass of moving ice form...
Important Question Answers for the Class 9-Social Science Chapter 2- Landforms: Earth's Living Canvas
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Very Short Answer Questions:
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1. Define plate tectonics.
Answer:- Plate tectonics is the theory that the Earth's lithosphere is divided into plates that move slowly over time.
2. Name the 3 main layers of the earth.
Answer:- The 3 main layers are
* Crust
* Mental
* Core
3. What is weathering?
Answer:- Weathering is the breaking of rocks into smaller pieces at the same place.
4. What is erosion?
Answer:- Erosion is the removal and transportation of weathered material from one place to another.
5. Name two agents of erosion.
Answer:- * Rivers
* Wind
6. What is a glacier?
Answer:- A glacier is a large mass of moving ice formed from compacted snow.
7. What is an earthquake?
Answer:- An earthquake is the sudden shaking of the Earth surface caused by movements inside the Earth.
8. What is a landslide?
Answer:- A landslide is the downward movement of rocks, soil and debris on a slope due to gravity.
9. What does GLOF stands for?
Answer:- GLOF stands for Glacial Lake Outburst Flood.
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Short Answer Type Questions
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1. Explain the theory of plate tectonics.
Answer:-
- Plate tectonics explains that the Earth's lithosphere is divided into large plates.
- These plates move slowly over the semi-fluid mantle.
- Their movement causes earthquakes, volcanoes, and mountain formation.
2. Describe the structure of the Earth.
Answer:-
- The Earth has three layers: crust, mantle, and core.
- The crust is the outermost layer, while the mantle lies beneath it.
- The core is the innermost layer and is mainly made of iron and nickel.
3. Differentiate between weathering and erosion.
Answer:-
| Weathering | Erosion |
|---|---|
| Breaking of rocks at the same place. | Removal and transport of weathered materials. |
| No movement of material occurs. | Material is carried away. |
| Caused by temperature, water, plants, etc. | Caused by rivers, wind, glaciers, and waves. |
4. Explain the work of rivers as agents of gradation.
Answer:-
- Rivers erode, transport, and deposit materials.
- In the upper course they form valleys, gorges, and waterfalls.
- In the lower course they deposit sediments and form floodplains and deltas.
5. How do waves shape coastal landforms?
Answer:-
- Sea waves continuously strike the coast and cause erosion.
- They remove materials from some places and deposit them in others.
- This process changes the shape of coastlines.
6. Describe the action of wind in deserts.
Answer:-
- Wind picks up sand and dust and transports them.
- It erodes rocks by rubbing sand particles against them.
- Wind also deposits sand to form dunes.
7. Explain the formation of U-shaped valleys.
Answer:-
- Glaciers move slowly over land carrying rocks and debris.
- They erode the sides and bottom of valleys.
- This erosion creates broad U-shaped valleys.
8. What are the causes of earthquakes?
Answer:-
- Movement of tectonic plates.
- Sudden release of energy inside the Earth.
- Activity along faults and plate boundaries.
9. Write short notes on landslides.
Answer:-
- Landslides involve the movement of rocks, soil, and debris down slopes.
- They are caused by heavy rainfall, earthquakes, and human activities.
- They can damage roads, houses, and agricultural land.
10. What is GLOF? Explain its impact.
Answer:-
- GLOF stands for Glacial Lake Outburst Flood.
- It occurs when water from a glacial lake is suddenly released.
- It can cause severe flooding, destruction of property, and loss of life.
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Long Answer Type Question:
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1. Explain the theory of plate tectonics with suitable examples.
Answer:-
Plate tectonics is the theory that the Earth's lithosphere is divided into large plates that move slowly over the semi-fluid mantle. These movements are caused by convection currents inside the Earth. The theory explains continental drift, earthquakes, volcanic activity, and mountain formation. For example, the Indian Plate colliding with the Eurasian Plate formed the Himalayas. Plate movements also create ocean trenches and volcanoes.
2. Describe the interior of the Earth with a neat labelled diagram.
Answer:-
The Earth is made up of three main layers:
Crust: The outermost and thinnest layer of the Earth.
Mantle: Located below the crust and extending to about 2900 km. It is made of hot semi-molten rocks.
Core: The innermost layer made mainly of iron and nickel. The outer core is liquid, while the inner core is solid.
Diagram Labels:
3. Explain different types of weathering with examples.
Answer:-
Weathering is of three types:
Physical Weathering: Rocks break into smaller pieces without changing their composition. Example: Rocks cracking due to heating and cooling.
Chemical Weathering: Minerals in rocks change due to chemical reactions. Example: Limestone dissolving in water.
Biological Weathering: Living organisms break rocks. Example: Tree roots growing into rock cracks.
These processes help in soil formation and landscape development.
4. Explain the role of rivers in erosion, transportation and deposition.
Answer:-
Rivers act as important agents of gradation.
Erosion: In the upper course, rivers cut deep valleys, gorges, rapids, and waterfalls.
Transportation: Rivers carry rocks, sand, and sediments downstream.
Deposition: In the lower course, rivers deposit sediments and form floodplains, distributaries, and deltas.
Thus, rivers continuously shape the Earth's surface.
5. Explain the work of glaciers as agents of gradation.
Answer:-
Glaciers are large moving masses of ice. As they move, they erode rocks and transport debris. They carve broad U-shaped valleys and carry sediments over long distances. When glaciers melt, they deposit materials in different places. Thus, glaciers modify landscapes through erosion, transportation, and deposition.
6. Describe the formation of coastal landforms by waves and currents.
Answer:-
Sea waves continuously strike the coast and erode rocks. They carry sediments from one place to another and deposit them along the shore. This process creates different coastal landforms and changes the coastline over time. Waves therefore act as important agents of erosion and deposition.
7. Explain the causes, effects and safety measures of earthquakes.
Answer:-
Causes:
- Movement of tectonic plates.
- Sudden release of energy inside the Earth.
- Activity along faults.
Effects:
- Collapse of buildings.
- Damage to roads and bridges.
- Loss of life and property.
Safety Measures:
- Construct earthquake-resistant buildings.
- Follow warning systems.
- Spread awareness and preparedness.
8. Describe landslides and avalanches with preventive measures.
Answer:-
Landslides:
Landslides are the downward movement of rocks, soil, and debris on slopes. They are caused by heavy rainfall, earthquakes, deforestation, and construction activities.
Avalanches:
Avalanches are rapid flows of snow, ice, and rocks down mountain slopes. They occur due to heavy snowfall, earthquakes, temperature changes, and human activities.
Preventive Measures:
- Afforestation.
- Retaining walls and protective barriers.
- Proper drainage systems.
- Early warning systems.
- Avoid construction in high-risk areas.
9. Explain Glacial Lake Outburst Flood (GLOF) and its impact on mountain regions.
Answer:-
A Glacial Lake Outburst Flood (GLOF) occurs when water stored in a glacial lake is suddenly released. This may happen due to glacier melting, weak moraine dams, earthquakes, or heavy rainfall.
Impacts:
- Severe flooding in mountain valleys.
- Damage to roads, bridges, and houses.
- Loss of agricultural land.
- Threat to human life and ecosystems.
Monitoring glacial lakes and early warning systems help reduce the risks.
10. Discuss dust storms and their effects in arid regions.
Answer:-
Dust storms occur when strong winds lift large amounts of dust and sand into the atmosphere. They are common in arid and semi-arid regions.
Effects:
- Reduced visibility.
- Respiratory and health problems.
- Damage to crops.
- Soil degradation.
- Disruption of transport and daily life.
Planting trees, conserving soil, and controlling land degradation help reduce the impact of dust storms.
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To Learn More NCERT Solutions Click Below:
Chapter 1- Social Science: Meaning, Scope and Importance- CLICK HERE
Chapter 2-Landforms: Earth's Living Canvas - CLICK HERE
Chapter 9-Understanding Democracy- CLICK HERE
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