Define the followings:
(i) Nuclear fission (ii) Nuclear fusion (iii) Binding energy.

Answer

(i) The phenomenon of splitting up of a heavy nucleus, on bombardment with slow speed neutrons, into two fragment of comparable mass, with the release of two or more fast moving neutrons and a large amount of energy, is known as nuclear fission.
`(##RES_PHY_CHM_V01_XI_C02_E01_034_S01##)`
(ii) The phenomenon of joining up of two light nuclei into a heavier nucleus is called fusion, e.q.,
`_(1)^(2)H+`_(1)^(3)H rarr `_(2)^(4)He+`_(0)^(1)n; (DeltaH=-17.6 MeV)`
(iii) The total energy given out during binding up to of nucieons in nucleus is known as binding energy. Greater is the binding energy, lesser will be the energy level of nucleus and thus, more will be its stability.