A circular coil of 60 turns and radius 4 cms is placed with

A circular coil of 60 turns and radius 4 cms is placed with its plane oriented at 90° to a magnetic field of 0.1 T. The field is now increased at a steady rate, reaching a value of 0.5 T after 3 seconds. What EMF is induced in the coil? A) 0.066 V B) 0.091 V C) 0.040 V D) 0.053 V E) 0.079 V

Solution

Emf = -d(phi)/dt

phi = B.A

phi = NBA*cos theta

angle will be zero between magnetic field and area of coil.

Emf = 60*3.14*0.04^2*cos(0)*(0.5 - 0.1)/3 = 0.0401 V

Ans is option C.