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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Magnetic Flux
Last modified on:8 years agoReading Time:2MinutesConsider a closed curve enclosing an area A (as shown in the figure). Let there be a uniform magnetic field B in that region. The magnetic flux through the area A is given by Φ = B.A = B A CosΘ where Θ is the angle which the vector B makes with…
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ELECTROMAGNETIC INDUCTION
Last modified on:5 years agoReading Time:2MinutesTopics to be covered: Electromagnetic induction; Faraday’s law, induced emf and current; Lenz’s Law, Eddy currents. Self and mutual inductance. Alternating currents, peak and rms value of alternating current/ voltage; reactance and impedance; LCR series circuit, resonance; Quality factor, power in AC circuits, wattless current. AC generator and transformer. Content: Introduction…
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Introduction (EMI)
Last modified on:5 years agoReading Time:2MinutesIn this lesson we will see how the current and emf are induced in a circuit when the magnetic flux through the circuit changes with time. In 1820, the connection between electricity and magnetism was demonstrated by Faraday and independently by Joseph Henry. They showed that an electric current could be induced in…
