# Phase velocity/propagation velocity?

1. Nov 25, 2007

### seang

what is the difference between the two, if any?

In particular, I'm working on this transmission line problem where I'm given the time delay and the length. I can solve to find some sort of velocity--is it the phase velocity, or propagation velocity?

I also have the equation lambda = vp * T. Again, is this phase velocity or propagation velocity?

Thanks,
Sean

2. Nov 26, 2007

### stewartcs

Sounds like Velocity of Propagation...not sure though.

Lambda = v*T = v/f

where,

v = velocity of propagation
T = period
f = frequency

Also, remember that c = f*lambda for free space (which is normally assumed for some applications).