There are two types of velocities associated with waves:
- Particle velocity
- Wave velocity
The SI unit of velocity is .
Particle velocity is the rate at which the medium's particles vibrate in order to transfer energy in the form of a wave.
The wave velocity is the velocity at which the wave travels through the medium. In other words, the velocity of a sound wave is the distance travelled by a sound wave in one unit of time.
It is mathematically represented as,
If one wavelength (λ) represents the distance travelled by one wave and one time period (\(T\)) represents the time taken for this propagation, the expression for velocity can be written as
As a result, the distance travelled by a sound wave per second can be defined as velocity.
Solids have the highest sound wave velocity because they are more elastic than liquids and gases. The velocity of sound in a gaseous medium is the lowest because gases are the least elastic.