SEBA Class 9 Social Science Chapter 6 Change of the Earth’s Surface

SEBA Class 9 Social Science Chapter 6 Change of the Earth’s Surface Solutions English Medium As Per New Edition Syllabus to each chapter is provided in the list so that you can easily browse through different chapters. SEBA Class 9 Social Science Chapter 6 Change of the Earth’s Surface Question Answer in English and select need one. SEBA Class 9 Social Science Textual Solutions Download PDF.

SEBA Class 9 Social Science Chapter 6 Change of the Earth’s Surface

SEBA Class 9 Social Science Chapter 6 Change of the Earth’s Surface Also, you can read the (SCERT) in these sections Solutions by Expert Teachers as per Board of Secondary Education, Assam (SEBA) Guidelines. SEBA Class 9 Social Science Chapter 6 Change of the Earth’s Surface. Here we have given SEBA Textual Solutions For Class 9 Social Science English Medium.

Change of the Earth’s Surface

GEOGRAPHY

EXERCISE

Give very short answer:

1. Give an outline of the distribution of continents and oceans of the world.

Ans: The surface of the Earth is divided into continents and oceans. Oceans, which are part of the hydrosphere, cover about 71% of the Earth’s surface. The remaining 29% is covered by landmasses or continents. These continents include various landforms like mountains, plains, plateaus, river valleys, deserts, and coastal plains.

2. Explain why there has been change over the earth’s surface.

Ans: The Earth’s surface changes over time due to the action of both internal (endogenic) and external (exogenic) forces. Endogenic forces like earthquakes and volcanic eruptions act from within the Earth, while exogenic forces like rivers, wind, rain, glaciers, and sea-waves operate from outside. These natural processes shape and reshape the landforms continuously.

3. What is meant by exogenic factor? Mention some exogenic factors.

Ans: Exogenic factors are external forces that act on the Earth’s surface and bring about gradual changes. These forces include sunshine, wind, rainfall, river, glacier, sea-waves, and even the action of plants and animals. They mainly come from the atmosphere and the energy of the sun.

4. Why are earthquakes and volcanic eruptions called endogenic factors.

Ans: Earthquakes and volcanic eruptions are called endogenic factors because they originate from within the Earth’s interior. These forces work invisibly beneath the surface and can cause sudden and major changes like the formation of mountains, land uplift, or land subsidence.

5. What do you mean by a river basin? Draw a diagram of a river basin.

Ans: A river basin is an area of land where a river and its tributaries collect and carry water downward. The water may come from rain, melted snow, or springs. The entire area drained by a river system is known as a basin.

The diagram is shown below –

6. What is a tributary? Name two major tributaries of the Brahmaputra.

Ans: A tributary is a smaller stream or river that flows into a main river. It helps to increase the water volume of the main river. Two important tributaries of the Brahmaputra River are the Subansiri and the Manas rivers.

7. Give an outline of river erosion.

Ans: River erosion occurs when the flowing water removes soil, sand, and rocks from the river channel and banks. Erosion is strongest in mountainous areas where the river flows fast. Factors like water speed, volume, and type of rocks influence the extent of erosion.

8. What do you mean by lateral erosion of a river?

Ans: Lateral erosion is the process by which a river widens its channel by eroding its banks. This usually happens in the plains where the river slows down and spreads sideways, cutting the banks and forming a wider, flatter channel.

9. What is ox-bow lake? Draw diagram to show how it is formed.

Ans: An ox-bow lake is a curved waterbody formed when a meandering river cuts off one of its loops to take a shorter, straighter path. The separated loop becomes a lake shaped like a horseshoe.

The diagram is shown below –

10. What is floodplain? Write how it is formed.

Ans: A floodplain is a flat area of land on either side of a river that gets covered by water during floods. It forms when the river deposits silt, mud, and sand during flooding. Over time, these deposits make the land fertile and good for agriculture.

11. Write how and where sandbars are formed in a river channel.

Ans: Sandbars are formed by the deposition of sand and sediments in the riverbed. They usually occur in the middle or sides of the river channel, especially when the river slows down in the plains. Their size and shape can change with seasons and water flow.

12. How are the deltas formed?

Ans: Deltas are formed at the mouths of rivers where they meet the sea or ocean. As the river slows down, it deposits large amounts of sediments, forming landmasses that look like a triangle or the Assamese letter “ব”. Famous deltas include the Ganga-Brahmaputra and Nile deltas.

13. Write why the wind action is strong in the deserts.

Ans: Wind action is strong in deserts because there is very little vegetation to block or slow down the wind. As a result, the wind can easily carry and move sand and dust from one place to another, causing erosion and forming desert landforms.

14. What is meant by deflation?

Ans: Deflation is the process by which wind removes loose sand and dust from the ground surface in desert areas. This makes the land lower and may even form shallow depressions.

15. How are the sand dunes formed?

Ans: Sand dunes are hills of sand formed by wind deposition. When wind carrying sand slows down or hits an obstacle, it drops the sand. Over time, the sand accumulates and forms dunes of different shapes and sizes.

16. What is inselberg?

Ans: An inselberg is a small, isolated hill that stands above a flat desert plain. It is formed when wind erodes the surrounding softer rocks, leaving behind the harder, resistant rock as a hill.

17. Define glacier and state how it differs from a river.

Ans: A glacier is a slow-moving mass of ice that flows down a slope, mostly found in polar and high mountain regions. Unlike rivers, glaciers carry frozen ice instead of liquid water and move more slowly, causing erosion in U-shaped valleys.

18. What is moraine? Draw a diagram to show different types of moraine.

Ans: Moraine is the rocky and sandy material carried by glaciers. There are four types: lateral (along the valley sides), ground (on the valley floor), medial (in the middle where two glaciers meet), and terminal (at the end of the glacier).

The diagram is shown below –

19. Write how a glacial horn is formed.

Ans: A glacial horn is a sharp, pointed mountain peak formed when several glaciers erode a mountain from different sides. This creates a steep, conical shape.

20. What is a coast?

Ans: A coast is the boundary where the land meets the ocean. It includes all the features and landforms found along the edge of the sea or ocean.

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SEBA Class 9 Social Science Solutions [New Editions Updated]

Sl. No.	CONTENTS
Chapter – 1	Advent of the Europeans into India
Chapter – 2	Growth of Indian Nationalism
Chapter – 3	The Moamoriya Rebellion
Chapter – 4	Burmese Invasion of Assam
Chapter – 5	Beginning of The British Administration in India
Chapter – 6	Change of the Earth’s Surface
Chapter – 7	Atmosphere: Structure, Air Pressure and Wind System
Chapter – 8	Geography of India
Chapter – 9	Geography of Assam
Chapter – 10	Political Parties in India
Chapter – 11	Types or Classification of Government
Chapter – 12	Basic Concepts of Economics
Chapter – 13	Basic Economic Problems