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Homework Help: Where is nuclear binding energy stored?

  1. Jul 12, 2017 #1
    • Member advised to use the homework template for posts in the homework forums of PF.
    I understand that the difference in mass between the protons and neutrons and the nucleus itself is called the mass defect, and that this mass defect is converted into nuclear binding energy. What seems to confuse me is where this energy is actually stored. I've been reading 4-5 different textbooks and several sources online but they seem to give conflicting perspectives on the matter. Some say that they are stored within the nucleus itself, whilst others say that they are "released", i.e. transferred to the surroundings. The latter makes more sense to me, as nuclear binding energy is officially defined as the amount of energy required to break apart the protons and neutrons and hence completely disassemble a nucleus.

    I'm genuinely confused and would appreciate any help.
  2. jcsd
  3. Jul 12, 2017 #2


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    Binding energy in an attractive potential is negative, so a bound system has less energy than its unbound components. This means that in the process of binding there is excess energy being released to the environment. Similarly, unbinding requires a supply of external energy.

    You could turn the argument around, and using the bound state as the baseline, ask where is the added energy stored when you unbind the components of the nucleus. In which case you could say that the extra energy you supplied is stored in the field (its potential energy).

    If nuclear forces are too far removed from your intuitions, try visualising the same thing using gravity. All these concepts apply there accordingly.
  4. Jul 12, 2017 #3
  5. Jul 12, 2017 #4
    Well explained!
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