How many degrees are there in one complete cycle of an AC sine wave?

A complete cycle of an AC sine wave encompasses a full oscillation from its starting point, through its peak, back to the starting point, and then to the negative peak, before returning again to the starting position. This entire process covers a rotation of 360 degrees on a unit circle.

In the context of AC power systems, this 360-degree cycle is essential because it represents the time it takes for an AC signal to go through all its phases—positive peak, zero, negative peak, and back to zero. Understanding this full cycle is vital for analyzing and designing electrical systems, as it directly relates to the frequency and timing of alternating currents.

Other angles, such as 180 degrees, 90 degrees, or 120 degrees, represent only portions of the sine wave cycle and do not reflect the complete oscillation of the wave. Hence, the correct answer is indeed 360 degrees, as it accurately describes the total phase shift in one complete cycle of an AC sine wave.