A coil with 20 circular turns each of diameter 60 mm is placed in a uniform magnetic field of flux density 90 mT.
Initially the plane of the coil is perpendicular to the magnetic field lines.
The coil is rotated about a vertical axis by 90° in a time of 0.20 s so that its plane becomes parallel to the field lines.
Assume that the rate of change of flux linkage remains constant.
What is the emf induced in the coil?