Key idea
Electromagnetic induction
ε = −dΦ_B/dt · Φ_B = ∫B
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.
Electromagnetic induction
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.
Why it matters
Generators, transformers and many sensors grow from this deceptively compact idea.
A picture to remember
Key idea
Electromagnetic induction
Guided example
Electromagnetic induction
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.
Put it into practice
Electromagnetic induction
Choose a concrete case linked to Electromagnetic induction. Write down the known information, what you are trying to find, and the units. Then state the rule, model or trend you will use. If a calculation is involved, keep the units visible at every line; if it is conceptual, state what changes and what remains fixed.
Check your answer
A strong answer contains four things: the starting situation, the variable that changes, the direction or numerical result, and one check. The check can be a unit, an order of magnitude, a limiting case or a comparison with a familiar example.