Question

A rectangular coil of area A, having the number of turns N is rotated at 'f' revolutions per second in a uniform magnetic field B, the field being perpendicular to the coil. Prove that the maximum emf induced in the coil is 2 πf NBA.

Answer 1

We know that flux is given by

`phi=NBACostheta`

we also know,

`e=-(dphi)/dt=(-NBA(-sintheta)(d theta)/dt)`

`=NBAsin theta(2pif)`

For maximum induced emf = sinθ = 1

`e_max=(-NBAsin theta (d theta)/dt)`

`=NBA(2pif)`

Hence proved.