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Homework Help: Pair Production in Vacuum

  1. Dec 17, 2009 #1
    1. The problem statement, all variables and given/known data

    What is the uncertainty in the life time of an electron and positron produced in a vacuum?

    2. Relevant equations

    [tex]\Delta E\Delta t=\frac{\hbar}{2}[/tex]

    3. The attempt at a solution

    [tex]\Delta E\approx1.6\times10^{-13}J[/tex]

    [tex]\Delta t\geq\frac{\hbar}{2\Delta E}\approx 3ps[/tex]

    (edited for Tex)
    This is the solution my professor had to this problem in his notes, but I am quite sure that the final answer of 3ps is a typo. I believe that Delta t is more like 3 x 10^-22 s. Can anyone clear this up for me?
    Last edited: Dec 17, 2009
  2. jcsd
  3. Dec 17, 2009 #2


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    Your answer seem right to me.
  4. Dec 17, 2009 #3
    Thanks! I had read over this part of the notes this morning right before the final exam. This problem ended up being on the exam. I could not for the life of me figure out why my answer was not 3ps :eek:.
  5. Dec 17, 2009 #4
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