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Science, (www.tiwariacademy.com), (Chapter - 15) (Some Natural Phenomena), (Class - 8), , €. Answer 6:, , Richter Scale measures the destructive energy of an earthquake. Yes, seismograph can measure an, earthquake of magnitude 3 on Richter Scale. It is of low intensity and will not cause any damage., , Question 7:, , Suggest three measures to protect ourselves from lightning., , €. Answer 7:, , Safety Measures during Lightning:, > Open space is dangerous. Take cover under a building., > Thunder storm is an indication to rush for safer place., > Once thundering stops, move out to an open place., , Question 8:, , Explain why a charged balloon is repelled by another charged balloon whereas an uncharged balloon, is attracted by another charged balloon?, , €. Answer 8:, , Two charged balloons have similar charges on the surfaces. Since like charges repel each other, that's, why one charged balloon is repelled by another charged balloon. When an uncharged balloon is, brought near a charged one, the uncharged balloon acquires some opposite charge. Since unlike, charges attract each other, therefore a charged balloon attracts an uncharged one., , Question 9:, , Describe with the help of a diagram an instrument which can be used to detect a charged body., €. Answer 9:, , Take an empty jam bottle. Take a piece of cardboard slightly bigger, , in size than the mouth of the bottle. Pierce a hole in it so that a metal, paper clip could be inserted. Cut two strips of aluminium foil about 4, cm x 1 cm each. Hang them on the paper clip as shown. Insert the, , paper clip in the cardboard lid so that it is perpendicular to it. Charge, , a refill and touch it with the end of the paper clip. See es, A simple electroscope, , The aluminium foil strips receive the same charge from the charged, , refill through the paper clip. The strips carrying similar charges repel each other and they become, wide open. Such a device can be used to detect whether an object is carrying charge or not. This device, is known as electroscope., , Question 10:, , List three states in India where earthquakes are more likely to strike., , €. Answer 10:, , Three states in India are Gujrat, Rajasthan and Himachal Pradesh., , In India, the areas most threatened are Kashmir, Western and Central Himalayas, the whole of NorthEast, Rann of Kutch, Rajasthan and the Indo - Gangetic Plane. Some areas of South India also fall in the, danger zone., , www.tiwariacademy.com, A Step towards free Education, a, , 2