# Phase velocity and group velocity

Forum Coordinator Posts: 0
Can anyone help me with how to differentiate phase velocity and group velocity?
Tagged:

• Pune, IndiaPosts: 167Forum Coordinator
Suppose, we add several waves together to create a resultant wave pattern. Each of these original waves can be of different velocity, amplitude and/or wavelength. So the velocity with which the phase of a single wave (original wave) travels is called phase velocity and the velocity of the resultant wave pattern refers to group velocity. Hope it addressed your concern!
• Posts: 540Forum Coordinator

Thank you for the response.

Is there any general relation between phase velocity and group velocity?

• Posts: 102Forum Coordinator

Hi,

The group velocity is directly proportional to the phase velocity and it differs for dispersive and non-dispersive waves. For non-dispersive waves, group velocity (Vg) is equal to the phase velocity (Vp) whereas, for dispersive waves Vg = Vp +k(dVp/dk), where is the angular wave number.

• Posts: 540Forum Coordinator
That really helped. Thank you!