Waves are one way in which energy may be transferred between stores. Both mechanical and electromagnetic waves will transfer energy but not matter.

The speed, or velocity, of a wave can be calculated using the equation:

wave speed = frequency × wavelength

This is when:

- wave speed (
*v*) is measured in metres per second (m/s) - frequency (
*f*) is measured in hertz (Hz) - wavelength (
*λ*) is measured in metres (m)

What is the speed of a sound wave that has a frequency of 50 Hz and a wavelength of 6 m?

wave speed = frequency × wavelength

wave speed = 50 × 6

wave speed = 300 m/s

- Question
What is the speed of a water wave with a frequency of 0.2 Hz and a wavelength of 25 m?

wave speed = frequency × wavelength

wave speed = 0.2 × 25

wave speed = 5 m/s

- Question
What is the wavelength of a radio wave with a frequency of 990 kHz and speed of 300,000,000 m/s?

wave speed = frequency × wavelength

990 kHz = 990,000 Hz