Final answer:
In an AC circuit with a pure inductor, the voltage leads the current by 90°.
Step-by-step explanation:
When a sinusoidal voltage is applied to a pure inductor in an AC circuit, the voltage leads the current by 90°. This means that the current lags behind the voltage by 90°.
In other words, the current waveform reaches its peak 1/4 cycle after the voltage waveform reaches its peak.
This phase relationship between voltage and current in a pure inductor is a characteristic of inductance.