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Some Natural Phenomena
How electrical discharge takes place in clouds?
The process of electrical discharge during lightning is explained as below:
1. During thunderstorms, the air currents move upwards while the water droplets moves downwards. 2. These vigorous movement causes seperation between the charges. The positive charges gets accumulated near the upper edges of the clouds and the negative charges near the lower edges of the clouds. The positive charge gets accumulated on the surface of the ground also.
3. When the magnitude of the accumulated charges becomes very large, the air which is normally a poor conductor of electricity, is no longer able to resist their flow.
4. When these negative and positive charges meet, electrical discharge takes place between clouds and grounds.
5. It produces huge amount of energy which is released as streaks of bright light and sound.
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Which of the following cannot be charged easily by friction?
When a glass rod is rubbed with a piece of silk cloth the rod
Write T against true and F against false in the following statements:
Like charges attract each other.
Write T against true and F against false in the following statements:
A charged glass rod attract a charged plastic straw.
Lightning conductor cannot protect a building from lightning.
Write T against true and F against false in the following statements:
Earthquakes can be predicted in advance.
Sometime, a crackling sound is heard while taking off sweater during winters. Explain.
Explain why a charged body loses its charge if we touch it with our hand.
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?
Suggest three measures to protect ourselves from lightning.
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