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E=hc/lambda C

  1. Feb 5, 2013 #1
    I was thinking about refraction and phase velocity change, when i thought about whether the c in e=hc/lambda is always 3x10^8 or does it refer to the speed in the medium?
    Thanks
     
  2. jcsd
  3. Feb 5, 2013 #2

    Simon Bridge

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    in ##E=hc/\lambda## ##c## is always the speed of light in vacuum.
    if the speed in the medium is important, it will show up in equations as a refractive index.
    as far as the photon is concerned, the "medium" is an array of atoms with empty space in between.
     
  4. Feb 6, 2013 #3
    So if wavelength decreases in a refractive medium, does that mean energy increases???
     
  5. Feb 6, 2013 #4

    Simon Bridge

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  6. Feb 6, 2013 #5
    It depends on what do you mean by λ. It is the wavelength in vacuum or in the medium?
    Anyway, you should have the formula getting back to E=hf which is valid in vacuum and media as well.
     
  7. Feb 6, 2013 #6
    Cheers folks. I now see that the qm and wave models must be evaluated differently and that E=hf is a more useful formula to employ :).
     
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