Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Phase velocity, Group velocity

  1. Dec 20, 2005 #1
    Would someone be kind enough to please give physical meanings to these two terms? I have never fully understood their meaning and difference (although I know how to express them mathematically).

    If, say, I have a Gaussian-shaped signal in the frequency domain that I am sending through a medium (such as a crystal) in the direction z say and I want to specify where the maximum intensity is as a function of t (it is at z=0 when t=0), am I right in saying that I would use:

    t= z/(group velocity)

    where the group velocity is obviously evaluated at the frequency of largest intensity.

    Any help on this fairly basic matter would be much appreciated.
  2. jcsd
  3. Dec 21, 2005 #2

    Doc Al

    User Avatar

    Staff: Mentor

  4. Dec 21, 2005 #3
    Thank you, I shall have a look but I actually think that I have a good enough understanding now having read a few relevant sections in the Feynman Lectures (sorry, this is what I should have done first).
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook