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Photon and free electron

  1. Apr 1, 2009 #1
    Why is it that a photon can't transfer all its energy to a free electron?
  2. jcsd
  3. Apr 1, 2009 #2


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    Staff: Mentor

    It's imposible to conserve both energy and momentum in such a process. You need another particle or object in order to do this.
  4. Apr 1, 2009 #3
    It's not the same thing, but there is a classical analogue of that fact: a ball of mass m cannot transfer all its kinetic energy to a ball of mass M=/=m.
  5. Apr 1, 2009 #4
    The only way for a photon to interact with a free electron (other than photoproduction at very high energies) is via Compton scattering.
  6. Apr 1, 2009 #5
    Last edited by a moderator: Apr 24, 2017
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