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Our Changing Earth Extra Questions Chapter 3 Class 7 Geography

Chapter 3 Our Changing Earth Extra Questions for Class 7 Geography with answers is very useful in knowing about important points given inside the chapter. You will get to know how questions can be framed in the examinations and prepare accordingly. Extra Questions for Class 7 will be helpful in scoring good marks in the exams.

Our Changing Earth Extra Questions Chapter 3 Class 7 Geography


Chapter 3 Our Changing Earth Very Short Answer Questions (VSAQs):


1. _______ is used to measure magnitude of earthquake.

Answer

Richter scale

2. Sudden movement in the earth interior are cause due to:

Answer

Endogenic force.

3. Define focus.

Answer

The place in the crust where the movement starts is called the focus.

4. The lithosphere is broken into number of plates known as ______.

Answer

Lithospheric plate.

5. The highest water fall is ____falls of Venezuela.

Answer

Angel.

6. A _____ is a vent in the earth crust through which molten material erupts suddenly.

Answer

Volcano.

7. What is vent?

Answer

The narrow opening of a volcanoes is called vent.

8. The depositional feature of a glacier is:

Answer

Moraine.

9. What is a river detla?

Answer

A river delta is a landform that forms at the mouth of a river, where the river flows.

10. When the rivers began to break up into a number of streams called _____.

Answer

Distributaries.

11. What is called a lava?

Answer

Rocks in the molten state are called magma. The magma when reaches the surface of the earth is called lava.

12. How are deltas formed?

Answer

Deltas are formed when rivers empty their water and sediment into another body of water.

13. Why do the plates move?

Answer

The plates move because of the movement of the molten magma inside the earth.

14. How is a waterfall formed?

Answer

When the river tumbles at steep angle over very hard rocks or down a steep valley side, it forms a waterfall.

Chapter 3 Our Changing Earth Short Answer Questions (SAQs):


1. What are glaciers? Describe their erosional and depositional activities.

Answer

Glaciers are rivers of ice which erode the landscape by clearing soil and stones to expose the solid rock below. Glaciers carve out deep hollows. As the ice melts they get filled up with water and become beautiful lakes in the mountains. The material carried by the glacier such as rocks big and small, sand and salt gets deposited. These deposits form glacial moraines.

2. What are volcanoes? Where are the volcanoes found?

Answer

A volcano is an opening in the earth’s crust which allows hot molten rock, ash and gases to escape from below the surface. Volcanoes are generally found where tectonic plates are pulled apart or come together. Volcanoes can also form where there is stretching and thinning of earth’s crust, such as in the (African) rift valley.

3. Define weathering.

Answer

Weathering is the process by which a bed rock may creemble or decay, because of the action of atmospheric moisture, rain, frost, temperature changes, chemical action or underlying water and other associated features.

4. What do you mean by lithospheric plates?

Answer

The solid crust of the rocks forming the surface of the earth is known as Lithosphere .The lithosphere is broken into a number of plates. These plates are known as lithospheric plates.

5. What do you mean by mushroom rocks?

Answer

An active agent of erosion and deposition in the deserts is wind. In desert we can see rocks in the shape of mushroom, commonly called mushroom rocks. The wind erodes the lower section of the rock more than the upper part.

6. What are meanders?

Answer

As the river enter the plains it twists and turns forming large bends known as meanders. Due to continuous erosion and deposition along the side of the meander, the ends of the meander loop come closer and closer.

7. What do you know about earthquake preparedness? Explain in a brief.

Answer

• Although earthquake cannot be predicted, the impact can certainly be minimised if we are prepared beforehand.
• If there is an earthquake, we should take shelter in a safe place without being panicked. We can get a safe spot under a kitchen counter, table or desk, against an inside corner or wall.
• We should stay away from fire places, areas around chimneys, windows that shatter including mirrors and picture frames, trees, electricity poles.

8. Define Loess.

Answer

When the grains of sand are very fine and light, the wind can carry it over very long distance. When such sand is deposited in large areas, it is termed as loess.

Chapter 3 Our Changing Earth Long Answer Questions (LAQs):


1. Give an account of the features made by a river.

Answer

A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river.The running water in the river erodes the landscape. When the river tumbles at steep valley side, it forms a waterfall.
• As the river enters the plain, it twists and turns forming large bends known as meanders.
• Due to continuous erosion and deposition along the sides of the meander, the ends of the meander loop come closer and closer. In due course of time the meander loop cuts off from the river and forms a cutoff lake, also known as oxbow lake.
• At times the river overflows its banks. This leads to the flooding of the neighbouring areas. As it floods, it deposits layers of fine soil and other material called sediments along its banks. This leads to the formation of a flat fertile floodplain.
• The raised banks are called levees. As the river approaches the sea, the speed of the flowing water decreases and the river breaks up into many distributaries. The river becomes so slow that it begins to deposit its load. Each distributary forms its own mouth. The collection of sediments from all the mouths form a delta.

2. How man is also responsible for earth quake?

Answer

Geologist and seismologist agree that humans can induce earthquake in five major ways of fluid injection into the earth, fluid extraction from the earthmining, nuclear testing and through the construction of dams and reservoirs. In fact, there are officially recorded instances of earth quake caused by human activity.
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