Question

A cylindrical bar magnet is kept along the axis of circular coil and near it as shown in Fig. Will there be any induced emf at the terminals of the coil, when magnet is rotated (a) about its own axis (b) about an aixs perpendicular to the length of the magnet ?

Answer 1

(a) When the magnet is rotated about its own axis, there is no change in magnetic flux linked with the coil. Therefore, induced emf = 0.
(b) When the magnet is rotated about an axis perpendicular to its length, orientation of the magnet flux linked with the coil changes. Hence an emf in induced in the coil.