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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Sound
Last modified on:5 years agoReading Time:37MinutesSound (i) The sensation felt by our ears is called sound. (ii) Sound is a form of energy which makes us hear. (iii) Law of conservation of energy is also applicable to sound. (iv) Sound travels in form of wave. Production of Sound Sound is produced when object vibrates or sound…
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Work & Energy
Last modified on:5 years agoReading Time:27Minutes Work For doing work, energy is required. • In animals, energy is supplied by food they eat. • In machine, energy is supplied by fuel. Not much work inspite of working hard : Reading, writing, drawing, thinking, analysing are all energy consuming. But in scientific manner, no work…
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Sound (SA)
Last modified on:5 years agoReading Time:13MinutesShort Answer Type Questions-I (2 Marks) 1. Three persons, A, B and C are made to hear a sound travelling through different mediums as given below : Persons Mediums A Iron Rod B Air C Water Who will hear the sound first? Why? [2011 (T-II)] 2. (i) Define the time period…
