Question

Which one of the following statements concerning an ac circuit is true?

A) The current and voltage are in phase for a capacitor in an ac circuit.
B) On average, the power dissipated by a resistor in an ac circuit is zero.
C) For a resistor in an ac circuit, the current and voltage are 90° out of phase.
D) Inductors in an ac circuit offer little opposition to current at high frequencies.
E) When only resistance is present in an ac circuit, voltage and current are in phase.

Answer 1

The true statement about an AC circuit is that when only resistance is present, voltage and current are in phase. This reflects the property of resistive components in an AC circuit and the fact that there is no phase difference between voltage and current. Therefore correct option is E

Step-by-step explanation:

The correct statement concerning an AC circuit is E) When only resistance is present in an AC circuit, voltage and current are in phase. This means that in a purely resistive AC circuit, the voltage across the resistor changes in the same way as the current through it, with no phase difference between them. Options A, B, and C are incorrect because for a capacitor, the current leads the voltage by 90°, and the power dissipated by a resistor in an AC circuit is not zero but varies depending on resistance and current squared. Option D is incorrect because inductors actually offer greater opposition to current at high frequencies, which is known as inductive reactance.