In an AC circuit, if a conductor is wound into a coil, what is the term for the EMF that opposes the supply voltage?

The term that describes the EMF that opposes the supply voltage in an AC circuit with a wound coil is inductive reactance. In an inductor, when alternating current flows through a coil of wire, it creates a magnetic field that changes as the current varies. This change in magnetic field generates an electromotive force (EMF) that opposes the change in current according to Lenz's Law.

This reaction is what is referred to as inductive reactance. Inductive reactance is a frequency-dependent opposition to the flow of AC, measured in ohms, and is specifically due to the inductance of the coil. The greater the frequency of the AC supply, the higher the inductive reactance will be.

Understanding inductive reactance is crucial in analyzing AC circuits, especially when calculating total impedance, which combines both the resistive and reactive components of the circuit.