Electromagnetic induction occurs when a magnet moves near a coil of wire. The effect of the induction is to produce an electric current whose strength depends upon the speed of motion, as well as upon the number of turns of the coil.
Overview
Michael Faraday stated that electromotive force (EMF) produced around a closed path isproportional to the rate of change of the magnetic flux through any surface bounded by that path. In practice, this means that an electric current will be induced in any closed circuit when themagnetic flux through a surface bounded by the conductor changes. This applies whether the field itself changes in strength or the conductor is moved through it.
In mathematical form, Faraday's law states that:
where
is the electromotive force
- ΦB is the magnetic flux.
For the special case of a coil of wire, composed of N loops with the same area, the equation becomes
A corollary of Faraday's Law, together with Ampère's law and Ohm's law is Lenz's law: The EMF induced in an electric circuit always acts in such a direction that the current it drives around the circuit opposes the change in magnetic flux which produces the EMF
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| Induction Process |
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