Question #c11d1

1 Answer
May 25, 2017

See below.


Ac generator works on the principle of Electromagnetic induction .
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consider the following Image .we know according to lenz law

hence there must be change in magnetic field in order to crate potential so , initially the loop is given a small torque as the arrow shown in the figure .

as the loop rotates in the magnetic field the force on the branch AB is shown by .

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here the Force #vecF# is the force on electrons and hence the direction of motion of electrons in magnetic field . Now the electrons move from D to C to B to A but current moves in opposite direction which is A to B to C to D .

But wait , we have to see that in AC generator there are slip rings due to which when the loop completes one cycle it the direction of current changes , for instance .enter image source here

in above figure if we start with #90^o# and go till #270^o# till that time A is negative and D is positive , but from #270^o# to #0^o# A becomes positive for that interval and D is negative for that interval .

In this way In one complete cycle it produces the AC current by different polarity of Terminal A and B .