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Homework Help: How exactly wud u do this

  1. May 3, 2004 #1
    gamma ray -> positron + electron

    calculate the min freq of the gamma ray photon required for this reaction occur.

    the reverse of the above reaction is pair annihiation. Write a reaction that represents pain annhiliation.
    I thought this would be positron + electron -> gamma ray
  2. jcsd
  3. May 3, 2004 #2
    Assume that after the reaction, both the positron and electron are at rest. What is the energy involved in the positron-electron system?

    This energy will be the same as on the left-hand side of the equation, except gamma rays have energy based on frequency. Set the two equal and solve for frequency.

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