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Why doesn't the photon

  1. Dec 4, 2009 #1
    ...become longer in its wavelength after it reflects off something? After all, photons do have momentum; I'd at least expect photons to transfer some of its energy to the object as it reflects off it, causing them to become less energetic, hence lengthening its wavelength.
    I'm mistaken, I know, but how so?...
     
  2. jcsd
  3. Dec 4, 2009 #2

    jtbell

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    Staff: Mentor

    You're not mistaken. However, try calculating how big this effect would be in a practical situation, and you'll probably get an idea of why people don't talk about it much.
     
  4. Dec 4, 2009 #3

    Matterwave

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    Compton scattering is a very analogous phenomenon to the one you are describing.
     
  5. Dec 4, 2009 #4

    jtbell

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    Sure, if a photon scatters off an individual electron or other elementary particle (Compton scattering is an example), or probably even an atom, the change in wavelength is noticeable. I had the impression Neo was thinking of macroscopic objects (maybe I was mistaken).
     
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