Electromagnetism: Electromagnetic Induction

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Electromagnetic Induction

Where an emf is induced by a change in the magnetic flux linking a circuit

Faraday's Law

The magnitude of the induced emf is proportional to the rate of change of magnetic flux

E = dΦ/dt

E = emf

Φ = magnetic flux

t = time

Lenz's Law

The direction of the induced emf always opposes the charge causing it

By combining Lenz's law with Faraday's law we get E = - dΦ/dt

Generators

Generators convert mechanical energy into electrical energy by rotating a coil of wire within a magnetic field.

This causes a constant change in the flux linking the coil, which induces an emf

Most generators set up alternating current, which is current whose direction reverses constantly

This is in contrast to direct current, which flows continuously in the same direction

http://www.youtube.com/watch?v=wchiNm1CgC4 (Einbetten)

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