With the help of a labelled diagram, describe the principle and working of an AC generator. Hence, obtain an expression for the instantaneous value of the emf generated.
A) An AC generator works by rotating a coil of wire in a magnetic field, inducing an alternating current.
B) An AC generator uses a stationary coil and a rotating magnetic field to produce an alternating current.
C) An AC generator operates based on the principle of electromagnetic induction, converting mechanical energy to electrical energy.
D) An AC generator produces a direct current by using a commutator to switch the direction of current flow.