Alternating current produced by the generator in a nuclear power plant is supplied to the primary coil of a transformer. Explain, with reference to Faraday's law of electromagnetic induction, how a current arises in the secondary coil.

A typical transformer consists of an iron core with two coils wound around it - the primary and the secondary. Any current-carrying wire produces a magnetic field around it, but because the primary coil carries an alternating current, it's going to produce a changing magnetic field. The alternating magnetic flux from the primary coil is going to penetrate the secondary coil.
Now, let's recall the Faraday's Law:
'The magnitude of an induced e.m.f is proportional to the rate of change of flux linkage'.
Since the flux is alternating, its rate of change cannot be zero or even constant - it has to be alternating as well. Therefore, a changing e.m.f is going to produce an AC in the secondary coil (provided it is a part of a closed circuit).