Answer: magnetic flux.
- A magnetic flux
- B electric charge
- C temperature
- D mass
Correct answer: A. magnetic flux
Explanation: A changing magnetic flux through a circuit induces an EMF (Faraday’s law).
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.