Question:

Example :A metal disc is made to spin at 20 revolutions per second about an axis passing through its centre and normal to its plane. The disc has a radius of 30 cm and spins in a uniform magnetic field of 0.20 T, which is parallel to the axis of rotation. Calculate (a) The area swept out per second by the radius of the disc, (b) The flux cut per second by a radius of the disc, (c) The induced emf in the disc.