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Question about photon absorbtion/emission by hydrogen

  1. Oct 4, 2011 #1
    I had this problem for my physics class where we had a 20eV photon interaction with hydrogen gas. It takes 13.6eV to knock electrons off of the atoms from the ground state after the photon is absorbed by the hydrogen atom, but that leaves 6.4eV left over.

    Does all of this energy go into the kinetic energy of the electron, or could another photon of, say, 3.2eV be emitted while the other 3.2eV goes into kinetic energy?
  2. jcsd
  3. Oct 5, 2011 #2


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    That's a good question. I'm pretty sure that the first one is termed the "photoelectric effect" and the second one termed "Compton scattering". Maybe someone who knows a bit more about it can give more info on the "when where why" of why one mechanism is favored over the other.
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