Confused about what my exam board wants!

BomboshMan

I'm doing AQA Physics A unit 5 next Monday, and I've been doing some past papers but i'm not sure about how to answer questions on the energy released in nuclear reactions. The mark schemes say that the energy released is equal to the change of binding energy per nucleon but I thought that the energy released is equal to the change of total binding energy, and it is this second one which is written in my text book. Which one is right, and if it is the per nucleon one which is right, why?

Thankaa :D

mfb

The total energy released/required in nuclear reactions is the change of the total binding energy (assuming that the number of particles stays the same, e.g. no neutron decay involved).
The energy released per nucleon is the total energy divided by the number of nucleons and therefore related to the binding energy per nucleon.