(Nuclear binding energy – conceptual explanation)
A nucleus is said to possess a “mass defect” when its actual mass is less than the sum of the separate masses of its constituent nucleons.
Answer the following questions in brief, taking suitable examples wherever required.
(i) Define mass defect of a nucleus.
(ii) Explain how the phenomenon of mass defect leads to the concept of nuclear binding energy. Why is this energy regarded as a measure of nuclear stability?
(iii) Describe qualitatively (without numerical calculation) how the average binding energy per nucleon varies with mass number. State what this trend implies for the feasibility of energy release through (a) fusion of light nuclei and (b) fission of very heavy nuclei.