Which of the following is the term for the opposition to current flow in an AC circuit?

The correct term for the opposition to current flow in an AC circuit is impedance. Impedance is a comprehensive measure that includes not only the resistance, which opposes the flow of direct current, but also the effects of reactance, which arises from the capacitive and inductive elements in the circuit. Reactance itself is frequency-dependent and is associated with how capacitors and inductors resist changes in current flow, but impedance encompasses both resistance and reactance, providing a complete picture of how an AC circuit will behave under various conditions.

In an AC circuit, both resistance (the opposition to current flow due to materials) and reactance (the opposition to changes in current flow due to inductors and capacitors) are important. However, impedance provides an overall description of total opposition that combines these aspects, which is essential for understanding AC circuit behavior.

Resistance refers specifically to the opposition to direct current (DC), while inductance is a property of inductors preventing sudden changes in current and contributes to reactance but does not describe the total opposition in AC circuits. Reactivity is not a standard term used to denote this opposition; the correct terminology that embodies both resistance and reactance in the context of AC is impedance.