Faraday's Law

The potential difference induced across the ends of a coil of wire is equal to the time rate of change of the magnetic flux through that coil of wire. This potential difference is known as an induced "electromotive force" or as an induced emf.

The flux through a loop of wire can change due to many different situations.

Anything that causes a change the the flux through a loop of wire produces a potential difference across the ends of the loop. If there are N loops, the potential differences across each of the loops will be added and the total potential difference will be N times that across the ends of a single loop.

Magnetic Flux

Lenz' Law

Return to Ch 21, Electromagnetic Induction
(c) Doug Davis, 2000; all rights reserved