Explain why the e.m.f. generated in a conductor of an
alternating-current generator is seldom sinusoidal.
A rectangular coil of 55 turns, carried by a spindle
placed at right angles to a magnetic field of uniform
density, is rotated at a constant speed. The mean area
per turn is 300 cm2. Calculate: (a) the speed in order
that the frequency of the generated e.m.f. may be
60 Hz; (b) the density of the magnetic field if the
r.m.s. value of the generated e.m.f. is 10 V.