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A Question about Mass Defects in Nuclear Reactions, and a few more general questions

  1. May 19, 2012 #1
    Hi, I have a question of mass defects in nuclear reactions, and some preliminary questions about nuclear reactions in general.

    First of all, can all nuclear reactions be classified as either fission, fusion, or radioactivity?

    Is there a mass defect / conversion of mass into energy in a radioactive process?

    Are alpha decays examples of fission reactions? Or do fission reactions only involve reactions that split up a nucleus into two "fairly large" nuclei?

    Do both fission reactions and fusion reactions involve a mass defect, with the mass of the products being less than the mass of the reactants?

    Are there any nuclear reactions in which there is a mass "excess," with the mass of the products being greater than that of the reactants? Is this even possible?

    As a continuation of the previous question, what is an example of a process in which energy has been converted to mass?

    Do the two equations E = mc^2 and E = nhc/lambda (where n is a positive integer) considered simultaneously imply that not only energy, but also mass, is quantized; and does it imply a minimum nonzero mass just as it implies minimum nonzero energy?

    Are extremely small processes that occur at the subatomic level such as hyperfine splitting involve energies that are, for atoms of the same element, quantized?

    Thanks guys.

    Last edited: May 19, 2012
  2. jcsd
  3. May 19, 2012 #2
    Re: A Question about Mass Defects in Nuclear Reactions, and a few more general questi

    Ok, some fairly quick answers...
    The above cover the majority, but there are some other types such as electron/neutrino capture.
    Mass into energy, yes. Apart from beta decays, though, radioactivity normally increases the mass defects of the resulting particles. Beta decays release energy because the mass of a neutron is more than that of the resulting proton, electron and antineutrino.
    The latter, though this is really just a question of definitions of terms. Fissions can also produce more than the two nuclei - typically a few neutrons may be released as well.
    Spontaneous reactions, yes. The only exception I can think of is the one in the answer to the next question.
    Yes, the reactions that produce the very heavy elements in the first place, such as in supernovae, are endothermic.
    Don't think so.
    Yes, the hyperfine splitting is just a very small difference between two quantised energy levels. See http://en.wikipedia.org/wiki/Hyperfine_structure.
    Last edited: May 19, 2012
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