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Homework Help: Group Velocity of light waves

  1. May 24, 2005 #1
    Dear Friends and Phorum,

    I need to know how to calculate the group velocity of light. I've read that's exactly "c", but I don't know how to calculate it.
     
  2. jcsd
  3. May 24, 2005 #2

    quasar987

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    How about this?

    [tex]c=\lambda \nu = \frac{2\pi}{2\pi}\lambda \nu = \frac{\omega}{k}[/tex]

    So the dispersion relation is

    [tex]\omega(k)=ck[/tex]

    There you go

    [tex]v_g=\frac{d\omega}{dk} = c[/tex]
     
  4. May 24, 2005 #3
    Thanks You

    Thanks quasar987
     
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