Frequency Counts Wave Cycles Per Second

Steps:

• Recall that waves consist of repeating patterns of crests and troughs, where one full cycle equals one wavelength.
• Identify the quantity that measures how many complete cycles (wavelengths) pass a fixed point in one second.
• Recognize this as a rate of oscillation, directly matching the definition provided.
• Confirm by linking to the wave equation: speed = frequency × wavelength, where frequency is cycles per second.

Why B is correct:

• Frequency is defined as the number of wavelengths (or cycles) passing a point per second, measured in hertz (Hz).

Why the others are wrong:

• A: Amplitude is the maximum displacement from equilibrium, measuring wave height, not rate.
• C: Speed is the distance a wave travels per second, not the number of wavelengths.
• D: Wavelength is the distance between consecutive crests, a spatial measure, not temporal.

Final answer: B