CBSE – 8th Standard Science

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Question Bank – Chapter 15 – Some Natural Phenomena

CHAPTER 15 

SOME NATURAL PHENOMENA

 

Q 1. Name some natural phenomena that cause destruction of human life?

Ans. Natural phenomena like thunderstorms, lightning, earthquake, Cyclone, tsunami cause large scale destruction of human life and property.

 

Q 2. What are predictable and unpredictable natural phenomena?

Ans. Cyclone, thunderstorms, lightning are predictable natural phenomena but tsunami and earthquake are unpredictable.

 

Q 3. What causes lightening?

Ans. The process of electric discharge between clouds and the earth or between different clouds causes lightning.

 

Q4. What is an Earthquake?

Ans. An earthquake is a sudden shaking or trembling of the earth lasting for a very short time caused by disturbance deep inside the earth’s crust. They can cause immense damage to buildings, bridges, dams can cause floods, landslides and tsunamis

 

Q 5. Explain why a charged body loses its charge if we touch it with our hand.

Ans. The process of transfer of charge from a charged objects to our hands causes flow of current thus discharging is done ,the process of transferring of charge from a charged object to the earth is called earthing.

 

Q 6. Name the scale on which the destructive energy of an earthquake is measured.

Ans. The power of an earthquake is expressed in terms of a magnitude on Richter scale, waves on the surface of the earth are called seismic waves. The waves are recorded by an instrument called the seismograph.

 

Q 7. Suggest some measures to protect ourselves from lightning.

Ans. Use of Lightning Conductor in buildings, Placing hands on knees with head between the hands, take shelter under small trees while lightening are the protective measures.

 

Q 8. List three states in India where earthquakes are more likely to strike.

Ans. Kashmir, Rajasthan, Rann of kachchh in Gujarat are in danger zone of earthquakes in India

 

Q 9. What precaution should be taken to protect our self from earthquake inside the house?

Ans. Take shelter under a table and stay there till shaking stops. Stay away from tall and heavy objects, Protect head with a pillow.

 

Q 10. What precaution should be taken to protect our self from earthquake outside?

Ans. Drop to the ground, try to find a clear spot, away from buildings, trees and overhead power lines can protect us from damage,  inside  car or a bus, do not come out, drive slowly to a clear spot. Do not come out till the tremors stop.

 

 

Try these :-

 

What causes thunder and lightning ?

Describe briefly the following terms:

  1. aftershocks
  1. b) convection currents

 

Describe how tsunamis form?

What causes an earthquake?

 

Fill in the blanks :-

  1. The electrical charges generated by rubbing are ______ .
  2. Tall buildings are protected from damage by lightning through a lightning ______ .
  3. The simplest form of a seismograph is a simple ______ .
  4. Magnitude and intensity of earthquake is measured by ______ scale.
  5. Lithosphere of earth is divided into about 20 parts called ______ plates.

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