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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Assertion Reason Questions for Biology Chapter 22 Chemical Coordination and Integration
Last modified on:5 years agoReading Time:22MinutesDirections: In the following questions, a statement of assertion is followed by a statement of reason.Mark the correct choice as:(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.(b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.(c)…
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Problems based on combination of resistance
Last modified on:4 years agoReading Time:5MinutesQ.1. For the circuit shown in below Figure, determine (a) the battery voltage V, (b) the total resistance of the circuit, and (c) the values of resistance of resistors R1, R2 and R3, given that the p.d’s across R1, R2 and R3 are 5 V, 2 V and 6 V respectively.…
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Numericals based on Resistivity
Last modified on:5 months agoReading Time:7MinutesNumerical Problems Q.1. Calculate the resistance of a copper wire of length 2m and area of cross section 10-6 m². Resistivity of copper is 1.7 x 10-8 Ωm Q.2. A copper wire of length 2m and area of cross section 1.7 x 10-6 m2 has a resistance of 2 x 10-2…
