Suppose that you wish to construct a simple AC generator with an output of 12 V maximum when rotated at 60 Hz. A magnetic field of 0.050 T is available. If the area of the rotating coil is 100 cm2, how many turns are needed?

Faraday's law: A changing magnetic field induces an emf.

Lenz's law:  current produced by an induced emf moves in a direction so that its magnetic field opposes the original change in flux.

The three ways that an emf can be induced in a loop of wire.
1. by changing the magnetic field
2. by changing the area of the loop in the field
3. by changing the loop's orientation with respect to the field