A pure inductor is connected to an AC power supply. In this circuit, the current
A) leads the voltage by 90°.
B) is in phase with the voltage.
C) lags the voltage by 45°.
D) lags the voltage by 90°.
E) leads the voltage by 45°.

Question

Quizplus · Accepted Answer

In a pure inductor, the voltage across the inductor leads the current by 90°. Using Ohm's Law, V = IXL, where V is voltage, I is current, and XL is the inductive reactance. Since XL = 2πfL, where f is the frequency of the AC power supply and L is the inductance of the inductor, the voltage across the inductor is directly proportional to the frequency of the AC power supply. Therefore, as the voltage alternates, the current will lag behind by 90°.

A Pure Inductor Is Connected to an AC Power Supply