Science

Some Natural Phenomena

Question:

Describe with the help of a diagram an instrument which can be used to detect a charged body.

Answer:

An electroscope can be used to detect whether a body is charged or not. The following figure shows a simple electroscope. It consists of a metal rod. At one end of the rod, two leaves of luminium foil are fixed and at the other end, there is a metal disc. The leaves of aluminium foil are placed inside a conical flask and the flask is corked to isolate the leaves from air. When the metal disc is touched with a charged body, the aluminium strips move away from each other. This happens because some of the charges of the body are transferred to the strips through the metal rod. This method of charging a body is called charging by conduction. The nature of charges on both the leaves and the charged body are the similar. Hence, both the leaves of the aluminium foil will move away from each other. If the body was not charged, then the leaves of the foil would remain as they were before. They would not repel each other.
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Some Natural Phenomena

Q 1.

Explain why a charged balloon is repelled by another charged balloon whereas an uncharged balloon is attracted by another charged balloon?

Q 2.

Suppose you are outside your home and an earthquake strikes. What precaution would you take to protect yourself?

Q 3.

Name the scale on which the destructive energy of an earthquake is measured. An earthquake measures 3 on this scale. Would it be recorded by a seismograph? Is it likely to cause much damage?

Q 4.

Describe with the help of a diagram an instrument which can be used to detect a charged body.

Q 5.

The weather department has predicted that a thunderstorm is likely to occur on a certain day. Suppose you have to go out on that day. Would you carry an umbrella?

Q 6.

Suggest three measures to protect ourselves from lightning.

Q 7.

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

Q 8.

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

Q 9.

Sometimes, a crackling sound is heard while taking off a sweater during winters.