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Homework Help: Finding Speed of Electron

  1. Nov 6, 2008 #1
    1. The problem statement, all variables and given/known data

    Beta decay is a radioactive decay in which a neutron in the nucleus of an atom breaks apart (decays) to form a proton and an electron. The electron is also known as a beta particle. The proton remains in the nucleus while the electron shoots out.

    Assuming that the neutron is at rest inside the nucleus, find the ratio of the speed of the electron to the speed of the proton just after the decay.

    2. Relevant equations

    3. The attempt at a solution

    I guess the only problem i have is where to find the speed of an electron after the decay. Does anybody know top hand or know where to search for the data?
  2. jcsd
  3. Nov 6, 2008 #2


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    Can you think of some quantity that is *conserved* during this process that might help you figure out what to do? (This is why we ask you to fill out part 2 of the template as well).
  4. Nov 6, 2008 #3
    Well the charge is conserved so wouldn't that leave the E=mc^2 equation. Once you get the energy, you can plug that value into the KE=0.5 mv^2 in order to get the velocity?
  5. Nov 6, 2008 #4
    I'll try to help you out a bit:

    Basically, since the electron and proton are breaking apart and flying in different directions, you must think about what is conserved.

    The immediate answer should be momentum. MeVe=MpVp

    Note you're looking for the ratio of the speed of the electron to proton.

    Good luck!
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