In a sine wave, the number of times per second the identical pattern repeats is known as the

• A. Amplitude
• B. Frequency
• C. Wavelength
• D. Phase

Answer: (B)

The main idea here is the rate at which the repeating pattern of a sine wave occurs over time. That rate is called frequency. It tells you how many cycles happen each second and is measured in hertz. For example, one cycle every second means a frequency of 1 Hz; if the cycle takes half a second, the frequency is 2 Hz. The period, the time for one full cycle, is the reciprocal of frequency (T = 1/f). The other terms describe different aspects: amplitude is how tall the wave is (maximum displacement), wavelength is the distance one cycle spans in space, and phase is the starting point or offset of the cycle. Since the question asks about how often the pattern repeats per second, frequency is the correct concept.