Thanks indianbaba :-D

One more point that I'd like to highlight here is about -

Why should all those powerful nations that posses H-Bomb act reluctantly towards using the same against any country?

The money / monetary help that would be required for rebuilding the ruined nation after the H-Bomb attack - would be coming from the UN and a major contribution to that fund comes from all these so called Nuclear capable countries. So, this kind of attack may be suicidal to them. Just a thought ....