A copper disc of radius 0.1 m rotates about its centre with 10 revolutions per second in a uniform magnetic field of 0.1 Tesla. The emf induced across the radius of the disc is
The induced emf between centre and rim of the rotating disc is
E=12BwR2=12× 0.1× 2π× 10× (0.1)2=10π× 10−3volt