Which statement best defines frequency?

• A. The pitch of the sound as heard by humans
• B. How often a sound repeats in a second
• C. A measure of the speed of the wave through a medium
• D. The rate at which energy is carried by the wave

Answer: (B)

Frequency is the rate at which a wave repeats its cycle in time, typically measured as cycles per second (hertz). This tells you how many crests pass a given point each second. In sound, frequency maps to pitch: higher frequency means higher pitch, lower frequency means lower pitch. The statement that best defines frequency is describing how often the sound repeats in a second. The other statements refer to related but different concepts: pitch is the perceptual result of frequency, wave speed is how fast the wave travels through a medium, and the rate at which energy is carried relates to energy or intensity, not repetition rate.