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Homework Help: Atomic physics - reaction and energy

  1. Dec 16, 2006 #1
    The problem statement, all variables and given/known data

    Which of the following reactions will release large amount of energy
    (1) Nuclear fusion
    (2) alpha - decay
    (3) Nuclear fission
    (4) gamma - decay

    two of the options are:

    B (1) and (3) only
    D (1), (2), (3), (4)



    2. Relevant equations
    none


    3. The attempt at a solution

    I tried D but the solution says it should be B.
    I don't understand why alpha - decay and gamma - decay do not give large amount of energy.
     
    Last edited: Dec 16, 2006
  2. jcsd
  3. Dec 16, 2006 #2

    rsk

    User Avatar

    If alpha decay gave off large amounts of energy, poor old Alexander Litvinenko might have met with a quicker, albeit more dramatic, end than the lingering one he suffered.....
     
  4. Dec 16, 2006 #3
    You are correct all 4 do give off LARGE amounts of energy (joules or kilo-watt hours), but only if your measure of “large” is in comparison to the amount of mass lost.
    All four use the same E=mc^2, so yes all for give a Large conversion to energy.

    But I’m sure the context of the question refers to power of each process in the amount of energy released in a unit of time (work, watts, joules/sec).
    Fission and Fusion converts much more mass much faster than decay does.
     
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