Science

Electromagnetic induction — The key idea

Start with the central idea, then test it against a concrete element or example. A scientific model is useful when we know what it explains — and where its limits are.

The key idea

Why it matters

A changing magnetic flux through a circuit is associated with an induced electromotive force. Faraday’s law quantifies the effect and Lenz’s law fixes its opposing sense.

A picture to remember

Generators, transformers and many sensors grow from this deceptively compact idea.

The key idea

Electromagnetic inductionε = −dΦ_B/dt

The key idea

A changing magnetic flux through a circuit is associated with an induced electromotive force. Faraday’s law quantifies the effect and Lenz’s law fixes its opposing sense.