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Homework Help: Binding energy of a nucleon virus an electron

  1. Apr 24, 2007 #1
    The energy that binds an orbiting electron to the hydrogen nucleus is 13.4 eV. Calculate the ratio of the binding energy per nucleon to the binding energy per electron in deuterium. Which part is held more tightly, the electron or the neutron?

    I already worked out the average binding energy per nucleon as 1.112 MeV/c^2 in the last question.

    1 eV = 1.0*10^6 MeV/C^2 (as per Google), so wouldn't that make the binding energy of an electron much stronger than that of a neutron?

    Do I have this mixed up?
  2. jcsd
  3. Apr 24, 2007 #2


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    It's really mixed up. Why are you dividing energies by c^2? Are you trying to convert to a rest mass? And in any event, 1eV=10^(-6)MeV. The neutron is way stronger bound. Take a stress pill and try to relax.
  4. Apr 25, 2007 #3
    Ah yes, ^(-6) makes all the difference in the world.

    I have divided energies by c^2 because mass and energy are interchangeable as per E=mc^2. The average binding energy is either (kg), (u), or (MeV/c^2).

    Using the revised equation, I conclude that the nucleon's average binding energy is approximately 83,000 times stronger than that of the the electron.

    Does anyone agree, or disagree?
    Last edited: Apr 25, 2007
  5. Apr 25, 2007 #4


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    Hard to argue with the numbers. BTW mass and energy are interchangeable - but they do have different units. It's a bit ungrammatical to call MeV/c^2 a 'binding energy'. It's a 'binding energy mass equivalent'.
  6. Apr 25, 2007 #5
    I find it a bit unorthodox myself but I am trying to stay within the confines of my text material.

    Thank you for your help.
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