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Homework Help: Nuclear Physics, photons, electrons and positrons

  1. Apr 21, 2009 #1
    1. The problem statement, all variables and given/known data
    A photon of sufficient energy can spontaneously create an electron and positron. This will conserve charge and must conserve energy. What is the minimum energy photon (in MeV and J) that can create an electron-positron pair?

    2. Relevant equations

    V=W/q (?)

    3. The attempt at a solution

    I know that the photon must have twice the energy of the electron (or of the electron and positron added together), but I have no idea how to find it. I think I am missing the formula or some simple conversion, help please!
  2. jcsd
  3. Apr 21, 2009 #2


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    Science Advisor
    Gold Member

    Rest energy of an electron: 511KeV

    Does that help?

    It's obtained by just using the E=mc^2 formula on the Electron's mass.
  4. Apr 21, 2009 #3
    Looks good to me! Thank you!
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