A closed-circuit, 500-turn coil, of resistance 100, and negligible inductance, is wound on a square frame of 40 cm side. The frame is pivoted at the mid points of two opposite sides and is rotated at 250 r/min in a uniform magnetic field of 60 mT. The field direction is at right angles to the axis of rotation.
For the instant that the e.m.f. is maximum :
(a) Draw a diagram of the coil, and indicate the direction of rotation, and of the current flow, the magnetic flux, the e.m.f. and the force exerted by the magnetic field on the conductors
(b) Calculate the e.m.f., the current and the torque, and hence verify that the mechanical power supply balanced the electric power produced.