Which term is used for energy storage in a magnetic field due to current?

• A. Relative motion
• B. Capacitance
• C. Inductance/Inductor
• D. Reactive power

Answer: (C)

Inductance is the property that describes storing energy in a magnetic field created by current. When current flows through a coil, it generates a magnetic field, and energy is stored in that field. The amount of energy is (1/2) L I^2, where L is the inductance and I is the current. Inductance also governs how voltage relates to changes in current: V = L di/dt, meaning a changing current builds or collapses the magnetic field, transferring energy in and out of the field. This is different from capacitance, which stores energy in an electric field from voltage, and from reactive power, which characterizes the exchange of energy between source and reactive elements in AC circuits rather than a stored energy at a given moment.