Nuclear fission is the phenomenon of splitting of a heavy nucleaus into two or more ligther nuclei. Nuclear fusion is the phenomenon of fusing two or more ligther nuclei to form a single heavy nucleus. In both these processes, certain mass `(Deltam)` disappears, which appears in the form of nuclear energy, `E=(Deltam)c^(2)`. The release of energy is so sudden that it cannot be controlled. This causes havoc. Nuclear fission is the basis of the an atom bomb and nuclear fusion is the basis of a hydrogen bomb. A powerful device, called Nuclear Reactor has been developed, where in nuclear energy produced is utilised for constructive purposes.
(i) How much energy is released in the fission of one nucleus of `U(235)` and in how much time?
(ii) Give an estimate of devastation potential of an atomic explosion.
(iii) Should we ban nuclear research in this field ? Give your views briefly.

Explanation

(i) form the fission of a single nucleus of `._(92)U^(235), 200 MeV` energy is released in `10^(-9)` second i.e., almost instantly.
(ii) First atomic explosion occurred in 1945 when an atom bomb was dropped on the city of Hiroshima, japan. This resulted in the killing of about 66000 people and grievous injury to an equal number. `2//3` rd of city structures were smashed and so on.
(iii) No, the reserch must go on. But we must investigate wasys and means for harnessing the enormous amount of nuclear energy for peacful purpose. Nuclear reactor is an outcome of that reseach.