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Question
Using the curve for the binding energy per nucleon as a function of mass number A, state clearly how the release in energy in the processes of nuclear fission and nuclear fusion can be explained.
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Solution

The rising of the binding energy curve at low mass numbers, indicates that energy will be released if two nuclides of small mass number combine to form a single middle-mass nuclide. This process is called nuclear fusion.
Highest peak (Fe) represents the most stable nucleus and all the other nuclei tend to achieve this state by undergoing nuclear reaction.
The eventual dropping of the binding energy curve at high mass numbers indicates that nucleons are more tightly bound when they are assembled into two middle-mass nuclides rather than into a single high-mass nuclide. Hence energy can be released by the nuclear fission, or splitting, of a single massive nucleus into two smaller fragments.
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