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Homework Help: Annihilation of electron and positron

  1. Jun 10, 2012 #1
    1. The problem statement, all variables and given/known data
    A positron with kinetic energy 2.2MeV collides with an electron at rest, and annihilate each other.
    a. Calculate the average energy of the two gamma photons produced as a result of annihilation

    2. Relevant equations

    3. The attempt at a solution
    I would infact calculate the energy in the left hand side including the rest masses.. isn't it.. So it would be (0.511 x 2) + 2.2 = 3.222 MeV .. But this doesn't seem the answer.. Any help guys???
  2. jcsd
  3. Jun 10, 2012 #2


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    Science Advisor
    Homework Helper

    hi ehabmozart! :smile:
    maybe they want you to divide by 2, for the average?
  4. Jun 10, 2012 #3
    Thanks.. I guess this gave me the answer... Dude, i will owe u if u just solve the question in this link.. Drivin' me crazy and no replies till now
    Here is the link "https://www.physicsforums.com/showthread.php?t=612956"
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