Sunday 27 December 2015

CLASS -VIII
ASSIGNMENT-SOME NATURAL PHENOMENON
1. Who invented the lightning conductor?

a. Alexander Fleming b. Graham Bell  c. Benjamin Franklin d. Thomas Alva Edison

2. What device is used to protect building from lightning?

a. Crescograph  b. Anemometer c. Lightning Conductor d. Barometer

3. What scale is used to measure the magnitude of earthquake?

a. Richter b. Celsius c. Fahrenheit d. Kilogram

4. The magnitude of earthquakes that occurred at Bhuj and

Kashmir was

a. less than 4 b. less than 2  c. less than 6  d. Higher than 7

5.It is a convention to call the charge acquired by a glass rod when it is rubbed with silk as ___________
 a) Negative b) Positive c) Neutral d) Can be any one

6 The power of an earthquake is expressed in terms of magnitude on a scale called
 a) Righter Scale b) Quake scale c) Richter Scale d) Earth Scale

7.Why does a plastic comb rubbed with dry hair attract tiny pieces of paper?

8.Rearrange the steps in the formation of lightning in the form of a flow chart.  

Air become charged, accumulation of charges, movements of air currents and water droplets, streaks of light and sound are produced.

9.. How can you charge the following objects?
. glass rod                    b. Ebonite rod

10.Explain three ways in which a body can be charges?

11.Draw the diagram of an instrument which can be used to detect charges on a body?

12. What is an lighting conductor?

13. What is earthing?why is earthing provided in buildings?

14. Suppose you are outside your house and an earthquake strikes. What precautions will you take to protect yourself?

15.Why is a crackling sound heard while taking out sweaters in winters?

16. What is the principle of an electroscope?

17. Distinguish static electricity from electric current.


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