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

Question

Quizplus · Accepted Answer

A resistor has a purely resistive nature, which means that it resists current flow irrespective of the voltage polarity. When an AC voltage is applied across the resistor, the resulting current through it varies in a similar fashion to the voltage waveform. However, there is no phase shift between the two. Since both the voltage and current in the resistor vary in-phase with each other, there is no time delay or phase shift between them. Therefore, the correct answer is C, that is the current is in phase with the voltage.

A Resistor Is Connected to an AC Power Supply