What is the term used to describe equivalent resistance in a magnetic circuit?

The term used to describe equivalent resistance in a magnetic circuit is "reluctance." This concept is analogous to resistance in an electrical circuit and reflects how easily magnetic flux can pass through a magnetic circuit. Just as resistance impedes the flow of electric current, reluctance impedes the flow of magnetic flux.

Reluctance is defined by the formula:

[ \text{Reluctance} (R) = \frac{l}{\mu A} ]

where ( l ) is the length of the magnetic path, ( \mu ) is the permeability of the material, and ( A ) is the cross-sectional area through which the flux flows. Higher reluctance indicates a greater difficulty for magnetic lines of force to pass, similar to how higher resistance indicates a more challenging path for electric current.

In this context, capacitance, impedance, and inductance refer to properties related to circuits but do not specifically pertain to the concept of magnetic resistance. Capacitance deals with the ability of a system to store electrical energy in an electric field, impedance combines resistance and reactance in AC circuits, and inductance relates specifically to the ability of a conductor to store energy in a magnetic field due to the flow of current.