CBSE Class 12-science Answered

Induced EMF E in the coil is , E = - N ( dΦ/dt ) .................... (1)

where N is number of turns in the coil ,  Φ = B × A is flux of magnetic field ,

B is magnetic field induction and A is area of coil .

Given magnetic field induction as a function of time is

B = B_o cos [ (2π / T ) t ]

where T is time period .

Hence , magnitude of induced EMF is

Above magnitude of induced EMF is maximum , if

[ (2π / T ) t ] = ( 2 n + 1 ) ( π / 2 )  , where n = 0, 1, 2 .... etc

Hence, magnitude of induced EMF is maximum when

t = (2n+1) ( T / 4 ) , where n = 0, 1, 2 .... etc