Which definition correctly describes the period of a wave?

• A. The time for one cycle
• B. The time for half a cycle
• C. The distance traveled in one cycle
• D. The frequency per second

Answer: (A)

Period is the time it takes for one complete cycle of the wave to pass a given point. That’s why the best definition is “the time for one cycle.” The period and frequency are reciprocal: T = 1/f. So a wave at 10 Hz has a period of 0.1 seconds. If you used half a cycle, you’d be describing half of the period, not the full cycle. The distance traveled in one cycle is the wavelength, not the period, and measuring frequency per second is just the frequency itself (in hertz), not the time for a full cycle.