In an alternating current circuit, a cycle is best described as:

• A. A single peak of voltage
• B. The average voltage over time
• C. A complete sequence where the current returns to its starting value
• D. The time between zero crossings

Answer: (C)

In alternating current, a cycle is one complete oscillation of the waveform—the current and voltage go through a full progression and return to the same state they started from. This is why the correct description is a complete sequence where the current returns to its starting value after one period. A single peak is only a momentary point on the curve, not the full repetition. The time between zero crossings is half the cycle (half-period), and the average voltage over a full cycle is typically zero for a symmetric AC signal, not the definition of a cycle.