Speed of a Wave Motion

Speed of a Wave Motion

The speed of a mechanical wave, is clearly expected to depend upon the properties of the medium through which the wave is travelling. The medium could be a solid, liquid or a gas. All the media are characterized by their physical properties, like mass, density, elasticity and temperature.

Waves are a disturbance which moves through space. Mechanical waves such as waves which propagate through water need a medium (the water) for them to exist. Electromagnetic radiation waves such as light and radio waves do not need a medium and can travel through a vacuum. 

To understand the concept of wave motion, we need to know about the three basic properties of waves.

Speed of a Wave Motion


Wavelength is denoted by λ. It it’s the distance between two consecutive crest and trough. Wavelength is measured in metres (m).


The amplitude (y) for the wave is given by the distance from the centre line to the top of the crest or the tip of a trough, the amplitude of the wave tells about the energy of the wave and amplitude is measured in metres (m).


Frequency is denoted by the symbol f and it is the number of waves passing through a point in one second and it is measured in hertz (Hz).

Speed of a wave is measured in metres per second. The speed of light is 3 x 10⁸ m/ sec.

Waves are categorised based on the way they propagate:

Transverse Waves:

Waves in which the particles in their medium move at right angles to the direction of wave motion.

Longitudinal Waves:

Waves in which particles move in the direction of wave propagation.

Spring of waves on string depends upon the tension and mass density of the string and is given by:

Speed of a Wave (v) = √(T/μ).

From the above relation, we can say that wave speed on a stretched depends on the tension in the string and the linear density of the string and not on the frequency of the wave.