Chapter: Shaping of the Earth’s Surface (Class 9 Social Science)
1. Who gave the theory of plate tectonics?
(a) Alfred Wegener (b) W.J. Morgan (c) Harry Hess (d) Tuzo Wilson
2. The semi-molten layer beneath the lithosphere that allows plate movement is called:
(a) Core (b) Asthenosphere (c) Lower mantle (d) Outer core
3. Which type of plate boundary is responsible for the formation of the Himalayas?
(a) Divergent (b) Transform (c) Convergent (continental-continental) (d) Convergent (oceanic-continental)
4. Weathering that involves the breaking of rocks due to plant roots growing into cracks is an example of:
(a) Physical weathering (b) Chemical weathering (c) Biological weathering (d) None of these
5. The Ring of Fire is associated with:
(a) Glacial landforms (b) Earthquakes and volcanoes along plate boundaries (c) Delta formation (d) Karst topography
6. Which of the following is not an agent of gradation?
(a) Running water (b) Glaciers (c) Volcanic eruption (d) Wind
7. Assertion (A): Transform plate boundaries mainly cause earthquakes.
Reason (R): At transform boundaries, plates slide past each other without creating or destroying crust.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
8. Assertion (A): Deltas are highly fertile and support agriculture.
Reason (R): Deltas are formed by the deposition of alluvium at the mouth of a river.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
9. The landform created when a river deposits sediment in a triangular shape at its mouth is called:
(a) Meander (b) Delta (c) Moraine (d) Yardang
10. Which disaster is caused by the sudden release of water from a glacial lake?
(a) Avalanche (b) GLOF (c) Dust storm (d) Landslide
11. Define plate tectonics.
12. Distinguish between weathering and erosion.
13. Name the three main types of plate boundaries.
14. What is a meander? Where is it commonly formed?
15. State any two human activities that increase the risk of landslides.
16. What are moraines? Name any two types.
17. Explain the role of convection currents in the movement of tectonic plates.
18. Differentiate between convergent and divergent plate boundaries with one example of each.
19. Describe any three types of weathering with examples.
20. How do rivers form V-shaped valleys, floodplains and deltas in their different courses?
21. Explain how erosion affects farmers and people living near coasts.
22. “Plate tectonics is responsible for the formation of many major landforms and natural disasters.” Analyse the statement with examples of mountains, earthquakes and volcanoes.
23. Describe the work of running water as an agent of gradation. Explain the landforms formed in the upper, middle and lower courses of a river.
24. “Landforms influence human life in multiple ways.” Justify the statement with reference to mountains, plains, deltas and coasts.
25. Read the source and answer the questions that follow:
“Plate tectonics is an important theory, given by W.J. Morgan, in earth science, that explains the movement of the Earth’s crust. According to this theory, the outermost layer of the Earth is not one single piece but is broken into several large and small pieces called tectonic plates. These plates move slowly over the semi-molten layer beneath them and are responsible for major physical features and natural phenomena, such as mountains, earthquakes, and volcanoes.”
(i) Who proposed the theory of plate tectonics? (1)
(ii) What are tectonic plates? (1)
(iii) Name the layer over which tectonic plates move. (1)
(iv) Mention any two natural phenomena caused by plate movement. (1)
26. Read the source and answer the questions that follow:
“Weathering is the process through which rocks on the Earth’s surface break down into smaller pieces due to various processes. It does not involve movement of the broken material, only the breaking down. There are three main types of weathering: physical weathering, in which rocks break into smaller pieces due to temperature changes, frost, or wind; chemical weathering, in which minerals in rocks change because of reactions with water, air, or acids… and biological weathering, which is caused by plants, animals, or micro-organisms.”
(i) Define weathering. (1)
(ii) State one difference between physical and chemical weathering. (1)
(iii) Give one example of biological weathering. (1)
(iv) Why is weathering important for soil formation? (1)
1. (b)
2. (b)
3. (c)
4. (c)
5. (b)
6. (c)
7. (a)
8. (a)
9. (b)
10. (b)
11. Plate tectonics is the theory that explains the movement of the Earth’s crust, which is broken into large and small tectonic plates that move over the semi-molten asthenosphere. (2 marks)
12. Weathering is the breaking down of rocks in situ; erosion involves the movement of weathered material by agents like water, wind or ice. (2 marks)
13. Convergent, divergent and transform boundaries. (2 marks)
14. A meander is a winding curve or bend in a river formed by lateral erosion and deposition in the middle or lower course. (2 marks)
15. Deforestation and road construction/mining on hillsides. (any two, 1 mark each)
16. Moraines are ridges of till (rocks and debris) deposited by glaciers. Types: lateral moraine, terminal moraine, medial moraine. (any two, 1 mark each)
17. Heat from the core causes molten material in the mantle to rise and cooler material to sink, creating convection currents that push and pull tectonic plates. (3 marks)
18. At convergent boundaries plates move towards each other (e.g., Himalayas); at divergent boundaries plates move apart (e.g., Mid-Atlantic Ridge). (3 marks)
19. Physical weathering (temperature/frost action), chemical weathering (reaction with water/air/acids), biological weathering (plant roots). (any three points, 1 mark each)
20. Upper course: V-shaped valleys and waterfalls due to steep gradient; middle course: meanders and floodplains; lower course: deltas and levees due to deposition. (3 marks)
21. Erosion removes fertile topsoil (farmers lose yield); washes away land, houses and roads near coasts/rivers. (3 marks)
22. Convergent boundaries form fold mountains (Himalayas); plate movements cause earthquakes and volcanoes especially along the Ring of Fire; explains distribution of continents and oceans. (any five relevant points)
23. Running water erodes, transports and deposits material. Upper course: V-shaped valleys, waterfalls; middle: meanders, oxbow lakes, floodplains; lower: deltas, levees, alluvial fans. (5 marks)
24. Mountains act as barriers/protectors and sources of rivers; plains and deltas support agriculture and dense settlements; coasts provide trade and harbours. (5 marks)
25. (i) W.J. Morgan (ii) Large and small pieces of the Earth’s crust (iii) Asthenosphere (iv) Mountains, earthquakes, volcanoes (any two)
26. (i) Breaking down of rocks in situ without movement (ii) Physical involves mechanical breakdown; chemical involves change in mineral composition (iii) Plant roots splitting rocks (iv) Produces fine particles that form soil (each 1 mark; source reference for each answer)
All questions are answerable from the NCERT chapter text. Reviewed by GFIS faculty.