(Qualitative)
A heavy nucleus undergoes nuclear fission into two medium–mass fragments.
(i) Define the terms (a) mass defect and (b) binding energy of a nucleus.
(ii) Starting from the definitions in part (i), show that the energy released in a fission reaction equals the difference between the total binding energies of the daughter nuclei and that of the parent nucleus. No numerical calculation is required.
(iii) The average binding energy per nucleon for very heavy nuclei is about 7.6MeV whereas for nuclei of mass number around 100 it is about 8.5MeV. Explain, with the help of this information, why energy is liberated when a 235U nucleus splits into two fragments of approximately equal mass.