Answer: Lenz's law or the right-hand rule.
- A Lenz's law or the right-hand rule
- B Ohm's basic circuit law
- C Coulomb's electric force law
- D Newton's second law of motion
Correct answer: A. Lenz's law or the right-hand rule
Explanation: Lenz's law, or equivalently Fleming's right-hand rule, gives the induced-current direction.
As a magnet approaches a coil, flux rises steadily and a constant non-zero EMF is induced (Faraday's law). Once the magnet stops moving, flux stays constant and the induced EMF drops to zero - EMF only exists while flux is actively changing.
Concept context
Faraday's and Lenz's laws, motional EMF, self/mutual inductance, eddy currents, and the AC generator - how a changing magnetic flux creates an electric current.