Define mutual inductance (M) and self-inductance (L), and their unit henry

Mutual Inductance (M): Mutual inductance is a property of a pair of coils that quantifies the effect of one coil's magnetic field on the other. When an alternating current is passed through one coil, it creates a changing magnetic field that induces a voltage in the second coil. The amount of induced voltage is directly proportional to the rate of change of current in the first coil. This proportionality constant is known as the mutual inductance, denoted by the symbol 'M'.

Self-Inductance (L): Self-inductance, or simply inductance, is a property of a single coil (or any conductor) that quantifies the effect of the coil's own changing magnetic field on itself. When an alternating current is passed through the coil, it creates a changing magnetic field that induces a voltage in the coil itself. This induced voltage is directly proportional to the rate of change of current in the coil. This proportionality constant is known as the self-inductance, denoted by the symbol 'L'.

The unit of both mutual inductance and self-inductance is the henry (H), named after the American scientist Joseph Henry. One henry is defined as the inductance of a circuit in which an electromotive force of one volt is induced when the electric current through the circuit is changing at the rate of one ampere per second.