Wavelength is the distance from one crest to another, or from one trough to another, of a wave. Crest is the highest point of the wave whereas trough is the lowest. Since wavelength is distance/ length, it is measured in units of length such as metres, centimetres, millimetres, nanometres etc. Wavelength is represented with the Greek letter lambda (λ). It is equal to the ration of the velocity of the wave and the frequency. Wavelength is expressed in units of meters (m).

\(Wavelength(\lambda )\,\,=\,\,\frac{Velocity\,\,of\,\,Wave(V)}{Frequnecy(f)}\).


λ = Wavelength, the distance between wave crest (m),

V = Velocity of Wave, the speed that waves are mobbing in a direction (m/ sec),

F = Frequency, the wave crests that go through a point in a certain time (Hz).

How to find Wavelength?

Problem: If the velocity of a wave is 60 m/sec and the frequency of the waves is 30 waves per second, then find the wavelength?

Solution: Given,

Speed of a wave (V) = 60 m/sec,

Frequency (F) = 30/ sec = 30 Hz,

Wavelength (λ) =?

We know that:

\(Wavelength(\lambda )\,\,=\,\,\frac{Velocity\,\,of\,\,Wave(V)}{Frequnecy(f)}\,\,=\,\,\frac{60m/\sec }{30/\sec }=2m\).

∴ Wavelength (λ) = 2m.