What phenomenon occurs when an AC voltage is applied to an inductor?

• A. The current leads the voltage
• B. The current lags behind the voltage
• C. Voltage remains constant
• D. Voltage leads the current

Answer: (B)

When an alternating current (AC) voltage is applied to an inductor, the current lags behind the voltage due to the nature of inductive reactance. Inductors store energy in a magnetic field when current flows through them, and this results in a phase shift between the voltage across the inductor and the current flowing through it.

Specifically, in an inductor, the voltage builds up to a peak before the current does, which means that there is a delay in the current reaching its maximum value compared to when the voltage reaches its peak. This is a fundamental characteristic of inductors in AC circuits, and it is described as the current lagging behind the voltage by a phase angle of up to 90 degrees, depending on the frequency of the AC signal and the reactance of the inductor.

This behavior is different from what occurs in resistive circuits, where the current and voltage are in phase, and capacitive circuits, where the current leads the voltage. Understanding this phase relationship is crucial for analyzing and designing AC circuits involving inductive components.