Table of Contents
Charging of Insulators
Since charge cannot flow through insulators, neither conduction nor induction can be used to charge, insulators, so in order to charge an insulator friction is used. Whenever an insulator is rubbed against a body exchange of electrons takes place between the two. This results in appearance of equal and opposite charges on the insulator and the other body. Thus the insulator is charged.
For example rubbing of plastic with fur, silk with glass causes charging of these things.
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COULOMB’S LAW
Last modified on:3 years agoReading Time:18MinutesCOULOMB’S LAW: Two point electric charges q1 and q2 at rest, separated by a distance r exert a force on each other whose magnitude is given by If between the two charges there is free space then Where ε0 is the absolute electric permittivity of the free space and ε0 =…
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If we comb our hair on a dry day and bring the comb near small pieces of paper, the comb attracts the pieces, why?
Last modified on:4 years agoReading Time:2Minutes If we comb our hair on a dry day and bring the comb near small pieces of paper, the comb attracts the pieces, why? Answer: This is an example of frictional electricity and induction. When we comb our hair, it gets positively charged by rubbing. When the comb is brought…
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Can two similarly charged bodies attract each other?
Last modified on:4 years agoReading Time:1Minute Yes, when the charge on one body Q is much greater than that on the other q and they are close enough to each other so that force of attraction between Q and induced charge on the other exceeds the force of repulsion between Q and q. However, two similar…
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Why does the earth rotate?
Last modified on:5 years agoReading Time:3MinutesThe reason for the rotation of earth and planets arise from the concept of formation of our solar system. In the beginning solar system was a big cloud of dust and gases. This cloud began to collapse, flattening into large disk, rotating faster and faster continuously, as they collapsed, their gravitational…
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Is light visible or invisible?
Last modified on:5 years agoReading Time:2MinutesLight is invisible until it hits an object. It can only be visible to us whenever it get scattered or bounced off the dust particles in the intervening medium. We can see the source of light like stars at night as they are too dim to light up much but that…
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POLAROID SUNGLASSES
Last modified on:5 years agoReading Time:4MinutesWe use polaroid sunglasses to minimise glare. When light is reflected from a bright non-metallic surface, it suffers partial plane polarisation. This means that more of the reflected light is vibrating in one plane than the other. For example, if you look at the morning sun reflected from a lake’s surface…
