The number of complete waves passing a fixed point each second is known as which quantity?

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

Answer: (A)

Frequency is the rate at which complete wave cycles pass a fixed point per unit time. It tells you how many waves occur each second and is measured in hertz. In this scenario, counting how many full waves pass the point every second gives you the frequency directly. Wavelength is the spatial distance between successive crests, not how often they pass per second. Amplitude describes the height of the wave, not its rate. Speed is how fast the wave travels; in a given medium, speed equals frequency times wavelength, linking these properties but not defining them. If five waves pass each second, the frequency is five hertz.