A wave with frequency 60 Hz and wavelength 3 m travels in a medium. What is its speed?

A wave with frequency 60 Hz and wavelength 3 m travels in a medium. What is its speed?

• A. 60 m/s
• B. 120 m/s
• C. 180 m/s
• D. 360 m/s

Answer: (C)

The main idea is that the speed of a wave in a given medium equals its frequency times its wavelength: v = f × λ. Here the frequency is 60 Hz and the wavelength is 3 m, so the speed is v = 60 × 3 = 180 m/s. The units make sense since Hz is per second and meters per second gives meters per second overall. This also shows why the other speeds wouldn’t fit: they would require different wavelengths at the same frequency (for example, 60 m/s would need a 1 m wavelength, 120 m/s would need 2 m, and 360 m/s would need 6 m).

The main idea is that the speed of a wave in a given medium equals its frequency times its wavelength: v = f × λ. Here the frequency is 60 Hz and the wavelength is 3 m, so the speed is v = 60 × 3 = 180 m/s. The units make sense since Hz is per second and meters per second gives meters per second overall. This also shows why the other speeds wouldn’t fit: they would require different wavelengths at the same frequency (for example, 60 m/s would need a 1 m wavelength, 120 m/s would need 2 m, and 360 m/s would need 6 m).