Electromagnetically Induced Current and Charge

Physics

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Factors affecting induced current

Induced current in the coil can be increased by increasing the number of turns in the coil, rapidly moving the coil and increasing the applied magnetic field.

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Direction of electric current in loops using Lenz's law

When the North-pole of a bar magnet is moved towards a closed loop like a coil connected to a galvanometer, the magnetic flux through the coil increases. Hence according to Lenz's law, current is induced in the coil in such a direction that it opposes the increase in flux.This is possible only if the current in the coil is in a counter-clockwise direction with respect to an observer situated on the side of the magnet.Note that magnetic moment associated with this current has North polarity towards the North-pole of the approaching magnet. Similarly, if the North pole of the magnet is being withdrawn from the coil, the magnetic flux through the coil will decrease. To counter this decrease in magnetic flux,the induced current in the coil flows in clockwise direction and its South pole faces the receding North-pole of the bar magnet. This would result in an attractive force which opposes the motion of the magnet and the corresponding decrease in flux.

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Faraday's Law of Induction

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Lenz's Law

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Effect of Variation of Magnetic Field, Flux and Area on Induced Emf

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Important Questions

State Faraday's law of electromagnetic induction.

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A coil having 500 square loops each of side 10 cm is placed normal to a magnetic field which increases at the rate of . The induced e.m.f. is

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Lenz's law is a consequence of law of conservation of

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A wheel with 10 metallic spokes each 0.5 m long is rotated with a speed of 120 rev/min in a plane normal to the earth's magnetic field at the place.If the magnetic of the field is 0.4G, what is the induced emf between the axle and the rim of the wheel ?

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The phenomenon of electromagnetic induction is :

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Two circular coils A and B are placed close to each other . If the current in the coil A is changed, some current be induced in the coil B. Give reason.

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The current flows from A to B as shown in figure, then the direction of the induced current in the loop will be

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There are two coils and as shown in Fig. A current starts flowing in as shown, when is moved towards and stops when stops moving. The current in is counter clockwise. is kept stationary when moves. We can infer that

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An air-cored solenoid with length 30 cm, area of cross-section  and number of turns 500, carries a current of 2.5 A. The current is suddenly switched off in a brief time of . How much is the average back emf induced across the ends of the open switch in the circuit? Ignore the variation in magnetic field near the ends of the solenoid.

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The magnetic flux linked with a coil is changed from Weber to weber in sec. Find the electromotive force induced in the coil.

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