Which parameter describes how fast a wave travels through the medium?

Which parameter describes how fast a wave travels through the medium?

• A. Period
• B. Frequency
• C. Wavelength
• D. Propagation speed

Answer: (D)

Propagation speed is the rate at which a wavefront moves through the medium, telling you how fast the disturbance travels. It depends on the medium and, for a given wave, is linked to frequency and wavelength by v = f × λ. The period is the time for one cycle, and the wavelength is the distance of one cycle; frequency is how many cycles occur per second (f = 1/T). These describe timing or spacing, not the actual travel rate. In many media the speed stays constant for different frequencies (non-dispersive), while in others it can vary with frequency (dispersive). For example, sound in air travels about 343 m/s, and a 1 kHz wave has a wavelength of roughly 0.343 m, consistent with v = f × λ.

Propagation speed is the rate at which a wavefront moves through the medium, telling you how fast the disturbance travels. It depends on the medium and, for a given wave, is linked to frequency and wavelength by v = f × λ. The period is the time for one cycle, and the wavelength is the distance of one cycle; frequency is how many cycles occur per second (f = 1/T). These describe timing or spacing, not the actual travel rate. In many media the speed stays constant for different frequencies (non-dispersive), while in others it can vary with frequency (dispersive). For example, sound in air travels about 343 m/s, and a 1 kHz wave has a wavelength of roughly 0.343 m, consistent with v = f × λ.