Phase/group velocity

1. Nov 9, 2004

Physicsiscool

Can anyone help me with this?

If w = square root of (gk) what is the phase and group velocity and show that the group velocity = v/2.

2. Nov 10, 2004

somy

Can you tell me what exactly the group velocity is???
I mean its definition. Thank a lot.
Somy

3. Nov 10, 2004

dextercioby

It's $$v_{g} =: \frac{d\omega(k)}{dk}$$,where the $$\omega(k)$$ is the dispersion relation.