Final answer:
In AC circuits, an inductor causes the sinusoidal voltage to lead the current by a phase angle of 90°.
The opposition to the change in current in an inductor is known as inductive reactance, similar to resistance in DC circuits, and is central to understanding the behavior of inductors in AC circuits.
Step-by-step explanation:
When dealing with an inductor in an AC (alternating current) circuit, there is a distinct behavior characterized by the voltage and current relationship.
In such circuits, when a sinusoidal voltage is applied to an inductor, there is a phase difference between voltage and current. Specifically, the voltage leads the current by one-fourth of a cycle or 90° phase angle.
This phase difference is indicative of how inductors react to sinusoidal AC voltage.
An inductor's opposition to a change in current is referred to as inductive reactance, which behaves similarly to resistance in DC circuits, but for AC circuits.
In this context, Ohm's law for an inductor gives us a way to calculate the voltage across the inductor (VL) related to the current through the inductor (IL) and the inductive reactance (XL) as VL = IL × XL, where XL has units of ohms (Ω).
When discussing ideal inductors, it is often assumed that they have negligible resistance, allowing us to focus on their inductive properties without the confounding effects of resistive heating or voltage drop due to resistance.