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Photon striking material

  1. Oct 15, 2005 #1

    From what i understand is that photons lose engery after being reflected off some material due to conservation of momentum (hitting electrons...). If they loses energy then their frequency is smaller, but how come when u look at a mirror you don't see a change in color the image in the mirror? is the change too small to be notice by the human eyes?

  2. jcsd
  3. Oct 15, 2005 #2


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    The short answer is "yes!"

    A photon's energy would have to be comparable to the electron rest energy (511 keV) in order for a substantial frequency change to occur. Typical photon energy in the visible range is about 1 eV.
  4. Oct 15, 2005 #3


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    It is unclear to what exactly is the phenomenon you are trying to describe here. If we go by simply with the title of your thread, then a photon actually does NOT lose energy after being reflected DUE to conservation of momentum. This is because the photon being reflected is actually a retransmission of the original photon by the conduction electrons on the surface of a metal, with a phase shift. Mirrors are typically made of metal films.

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