Answer: mutual inductance.
- A mutual inductance
- B self-inductance
- C the resistance
- D the capacitance
Correct answer: A. mutual inductance
Explanation: M is the mutual inductance linking the changing current in one coil to the EMF in the other.
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.