So, if the wavelength is γ,
Therefore, the distance travelled in the time of 1 complete vibration = γ
So, the distance travelled in the time of f complete vibrations = fγ
If the time period is T, than in T second, the number of vibration is 1
Therefore, the number of vibration in one second is = 1/T
The number of vibration in 1 second is frequency. So, the frequency, f = 1/T
Since the frequency is f, so f numbers of waves are produced in 1 second.
So, the distance travelled in one second by the wave = fγ
This is the velocity of wave, v.
Therefore, velocity of wave, v = fγ.