# Binding energy per nucleon and fission/fusion

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1. Jun 16, 2015

### Hashiramasenju

1. The problem statement, all variables and given/known data
Ok so i know that the binding energy per nucleon inceases after fission and fusion and the difference in the binding energy is given out as energy. But if the binding enrgy increases shouldnt there be energy taken in(rather than given out)? Also why is the net loss in my = the gain in Binding energy of the fused(OR FISSION EITHRER WAY) nuclei ?

2. Relevant equations

3. The attempt at a solution

2. Jun 16, 2015

### Staff: Mentor

Think of binding energy as negative: it's energy that's "missing" from the nucleus, compared to the separated nucleons; it's not energy that the nucleus "has".

3. Jun 16, 2015

### Hashiramasenju

Thanks for the reply kinda got it. But in the exam i get question like calculate the difference in mass and hence the energy released. Does this equal to the difference in binding energy.
And one question was"explain fission and fusion in terms of the binding energy" How do you Answer that? Thanx alot.

4. Jun 16, 2015

### Staff: Mentor

No, you have to convert from mass to energy. Try adding up the mass of 2 protons and 2 neutrons and subtracting the mass of an alpha particle from that sum. Then convert that difference in mass to energy.

Well, if binding energy is negative, meaning that an increase in binding energy gives off energy, what happens during fission and fusion?