AP Physics 2 / Unit 12: Magnetism and Electromagnetism
12.4 Electromagnetic Induction and Faraday's Law
Notes
A changing magnetic flux $\Phi=BA\cos\theta$ induces an emf:
$$\varepsilon=-N\frac{\Delta\Phi}{\Delta t}$$
- Lenz's law: the induced current opposes the change in flux.
Practice
Which induces a current in a loop?
Change is required.
Flux changes by 0.6 Wb in 0.2 s through a 1-turn loop. $|\varepsilon|=$
$\displaystyle \frac{0.6}{0.2}$.
Lenz's law says the induced current:
Conservation of energy.
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