Chapter 3 - Our Changing Earth Extra Questions
Multiple Choice Questions1. The earth’s crust is broken into a number of huge parts. They are called
a) lithospheric plates
b) metamorphic plates
c) sedimentary plates
d) none of these
Answer: a) lithospheric plates
2. Which one of the following forces originates in the interior of the earth?
a) Exogenic forces
b) Endogenic forces
c) Option a) and b)
d) None of these
Answer: b) Endogenic forces
3. Sudden movements in the earth are called
a) building mountains
b) earthquakes
c) focus
d) none of these
Answer: b) earthquakes
4. The place on the surface above the focus is known as
a) epicentre
b) focus
c) forces
d) All of these
Answer: a) epicentre
5. Name the instrument which used for measuring earthquake.
a) Thermometer
b) Seismograph
c) Option a) and b)
d) None of these
Answer: b) Seismograph
6. In which continent is the highest waterfall ‘Angel Falls of Venezuela’ located?
a) South America
b) South Africa
c) South Asia
d) South Australia
Answer: a) South America
7. Where is ‘Niagara falls’ located?
a) On the border between India and China
b) On the border between India and Pakistan
c) On the border between Canada and USA
d) On the border between India and Afghanistan
Answer: c) On the border between Canada and USA
8. The triangular collection of sediments at the mouth of a river forms
a) beach
b) delta
c) ox-bow lake
d) glaciers
Answer: b) delta
9. The steep rocky coast rising almost vertically above the sea water is called
a) sea cliff
b) beach
c) sea cave
d) erosion
Answer: a) sea cliff
10. Where is ‘Victoria Falls’ located?
a) On the borders between Saudi Arabia and United Arab Emirates
b) On the borders between Germany and Luxembourg
c) On the borders between Zambia and Zimbabwe
d) On the borders of Russia and China
Answer: c) On the borders between Zambia and Zimbabwe
11. The raised banks are called
a) Levees
b) Ox-bow lake
c) Floodplains
d) Meanders
Answer: a) Levees
12. Large deposits of loess is found in
a) Egypt
b) Libya
c) China
d) Nigeria
Answer: c) China
Answer the following questions:
13. What is earthquake? Give an account of earthquake preparedness.
Answer: The movement of lithospheric plates, causing the vibration on the surface of the Earth, these vibrations are called earthquake.
Earthquake preparedness
• One must stay indoors until the shaking stops.
• One must stay away from bookshelf and heavy things.
• The shelter must be under table or a bed.
14. How is glacier moraines formed?
Answer: Glacier carves out deep hallows. As the ice melts they get filled with water and become beautiful lakes in the mountains. The material carried by the glacier such as rock-big and small, sand and silt gets deposited. These deposits form glacier moraine.
15. What is delta?
Answer: Delta is a triangular land form that a river forms near its mouth (where it meets the ocean or sea). Since, river deposits most of its sediments near the mouth, these deposited sediments force the river to split in several distributaries and this region is called delta.
16. What are the two types of the earth’s forces?
Answer: The earth’s movements are divided on the basis of the forces which cause them. The forces which act in the interior of the earth are called endogenic forces. The forces that work on the surface of the earth are called exogenic forces. Endogenic forces sometimes produce sudden movements. At other times they produce slow movements. Sudden movements are earthquakes and volcanoes. They cause mass destruction over the surface of the earth.
17. What is a volcano?
Answer: A volcano is a vent or a hole in the earth’s crust through which molten material erupts suddenly.
18. What are three types of earthquake waves?
Answer: The three types of earthquake waves are
• P waves or longitudinal.
• S waves or transverse waves.
• L waves or surface waves.
19. What is a waterfall? Explain with example.
Answer: When the rivers tumble at steep angle over the hard rocks of a deep steep valley it forms a waterfall. For example: Niagara waterfall on the borders between USA and Canada
20. Explain why some rocks have a shape of mushroom.
Answer: Some rocks are in a shape of mushroom because in the desert the active agent is wind. Due to wind, the lower section of wind is eroded more than the upper section.
21. Why are floodplains so fertile?
Answer: The floodplains are so fertile because they are formed on the flooding of rivers, by the deposit of fine soil layers and other material called sediments along with the bank of river.
Fill in the blanks
22. A volcano is a vent in the earth’s crust through which molten material comes
out.
23. The place in the crust where the earthquake starts is called epicentre.
24. Deposition of layers of fine soil along the bank of rivers forms floodplains.
25. Sand deposits over larger areas are called loess.
26. When the river tumbles at steep angle over very hard rocks or down a steep valley side it forms a waterfall.
27. The magnitude of the earthquake is measured on the Richter scale.
28. There are 3 types of Earthquake waves.
29. The word Endogenic is made up of 2 words, Endo meaning inside and genic meaning origin.
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