Plot a graph showing the variation of binding energy per nucleon as a function of mass number. Which property of nuclear force explains the approximate constancy of binding energy in the range 30 < A < 170? How does one explain the release of energy in both the processes of nuclear fission and fusion from the graph?
Binding energy of a nucleon quantifies the stability of a nucleus where higher the binding energy, more is the stability. The Binding energy curve is plotted as follows:
The constancy of Binding energy in the range 30<A<170 refers to the saturation effect of the nuclear force. The neutron-proton ratio is higher in this region and hence the stability is higher.
In nuclear fission, a heavier nucleus disintegrates into lighter nuclei. The mass of the products is less than the mass of the reactants as some of its mass is converted into energy.
In nuclear fusion, we bring two light nuclei together and the energy released is equal to the energy required to overcome the repulsive forces while fusing.