What is the name of the effect in which a changing magnetic field induces an electric field?

Electromagnetic induction is the effect in which a changing magnetic field induces an electric field.

Michael Faraday discovered the phenomenon experimentally in 1831. Moving a magnet through a coil, or changing the current in a nearby coil, produced an induced electromotive force. The effect depends on changing magnetic flux rather than simply having a magnetic field present.

Faraday’s law quantifies the induced voltage as proportional to the rate of change of magnetic flux. The induced effect opposes the change that produces it, a direction described by Lenz’s law.

Electromagnetic induction underlies generators, transformers, induction cookers and many sensors. A stationary magnet near a stationary coil does not continually generate current; relative change is essential.