Electromagnetic Induction

Electromagnetic induction is the production of an e.m.f. when the magnetic flux linked with a conductor or coil changes. A changing magnetic field is therefore able to produce an electrical effect.

Induced e.m.f. can be produced by: moving a magnet toward or away from a coil; moving the coil through a magnetic field; * changing the current in a nearby coil.

Magnetic flux can be written as: **Φ = BA cosθ For a coil of `N` turns, flux linkage is: NΦ** Changing this flux linkage produces an induced e.m.f.

The induced e.m.f. becomes larger when: magnetic field changes more quickly; magnet moves faster; coil has more turns; field is stronger.