Imp Questions For All Chapters – Geography Class 9th
Short Questions
1. What are exogenetic processes?
- Processes on the Earth’s surface that form or break landforms.
2. Name one force behind external processes.
- Gravitational force.
3. What are primary landforms?
- Landforms made by internal Earth movements, like mountains.
4. Give an example of a tertiary landform.
- Delta.
5. What is mechanical weathering?
- Breaking rocks into smaller pieces without chemical change.
6. What causes exfoliation?
- Heating and cooling peel off rock layers.
7. How does frost break rocks?
- Frozen water expands in cracks and shatters rocks.
8. What is block disintegration?
- Big rock blocks separate due to temperature and water.
9. What is chemical weathering?
- Breaking rocks by changing their chemical structure.
10. What happens in carbonation?
- Rainwater with carbon dioxide dissolves rocks like limestone.
11. What is oxidation in rocks?
- Iron reacts with water and oxygen, forming rust.
12. How do roots cause weathering?
- They grow into cracks and split rocks.
13. What are burrowing animals?
- Animals like ants that dig into the ground.
14. What is mass wasting?
- Weathered rocks moving down slopes due to gravity.
15. What is a landslide?
- A rapid slide of rocks and soil down a slope.
16. What is slumping?
- Weathered material sinks in place.
17. What is soil creep?
- Slow movement of soil down a gentle slope.
18. Name one agent of erosion.
- Wind.
19. What is granular weathering?
- Rocks like sandstone break into loose particles by water.
20. What helps biological weathering on rocks?
- Moss and lichens.
Long Questions
1. How does temperature cause mechanical weathering?
- Temperature changes make rocks expand when hot and contract when cold, creating cracks over time. This happens a lot in deserts where the day is hot and the night is cold, breaking rocks apart.
2. What is frost weathering and how does it work?
- Frost weathering happens when water in rock cracks freezes and expands, putting pressure on the rock. This pressure breaks the rock into pieces, especially in cold places where temperatures drop below 0°C.
3. How does crystal growth break rocks?
- On rocky coasts, alkaline seawater enters cracks, and when it evaporates, crystals form and grow bigger. These crystals push against the rock, making holes that look like a honeycomb.
4. Why is water important in chemical weathering?
- Water acts like a solvent, dissolving minerals in rocks and making them weak. In rainy areas, it mixes with gases like carbon dioxide to form acids that break rocks faster.
5. What is carbonation and how does it affect rocks?
- Carbonation is when rainwater mixes with carbon dioxide to make carbonic acid, which dissolves rocks like limestone. This process is common in wet climates and changes the rock’s structure.
6. How does oxidation change rocks?
- Oxidation happens when iron in rocks reacts with water and oxygen, forming a reddish rust layer. This rust weakens the rock and is seen in places with lots of rain.
7. How do plants and animals cause biological weathering?
- Plant roots grow into rock cracks and break them as they get bigger, while animals like ants dig burrows that loosen rocks. Both make rocks split apart over time.
8. What is the difference between rapid and slow mass movements?
- Rapid mass movements, like landslides, happen fast on steep slopes and can destroy things, while slow ones, like soil creep, move gradually on gentle slopes. Rapid ones need rain or earthquakes, but slow ones happen naturally over time.
9. How does rain cause mass movements?
- Rainwater soaks into weathered rocks on slopes, making them heavy and unstable. This extra weight makes the rocks slide down fast, like in a mudslide.
10. What are the agents of erosion and what do they do?
- Agents like wind, water, glaciers, and seawater wear away rocks and carry them to new places. They shape the Earth by making landforms like valleys and dunes.
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