What does inductance oppose in an AC system?

Inductance in an AC system specifically opposes changes in current. This stems from the fundamental properties of inductors, which are components designed to store electrical energy in a magnetic field when current flows through them. When there is a change in current, the inductor will generate a counter electromotive force (EMF) that resists changes in that current flow. This phenomenon is quantified by the concept of inductive reactance, which is a measure of how much an inductor opposes alternating current as it changes direction.

In contrast, voltage is an electrical potential difference and does not inherently have a characteristic that can be directly opposed by inductance. Similarly, resistance is a separate aspect that deals with the opposition to current flow regardless of its changes. Lastly, power factor represents the phase difference between voltage and current in AC systems and is affected by both inductance and resistance but is not something inductance opposes directly. Therefore, recognizing that inductance's primary role in an AC circuit is to resist any rapid changes in current provides clarity on why changes in current is the correct choice.