Another option was to wage a full scale naval invasion, which would have resulted in a LARGER number of deaths in Japan (since even the civilians were told that every man woman and child should fight to the death if invaded), and would have resulted in the deaths of many many allied soldiers.
End WW2, ASAP.
japan surrendered
I think the only good reason was to bring the war to an end.
If you are referring to WW2, then the US stopped using atomic bombs on Japan because Japan agreed to surrender. Had they not, the US had plans and production setup to drop a total of 23 atomic bombs on Japan in 1945.
Using the atomic bomb would ultimately save more American lives by making a full-scale land invasion unnecessary.
He wanted to end that war and collapse the ability so the Japan could not make war again.
It was decided to build them to protect against Germany building and using them. It was decided to use them on Japan to end the war ASAP and save lives.
They kill.
The reason why the US used the atomic bomb against Japan was that the US wished to bring the war to a more rapid conclusion, in order to avoid giving the Soviet Union the opportunity to invade and take over Japan, as the Soviet Union had already done in Eastern Europe as a by-product of their fight against the Third Reich.
It depends to the countries and what resources they have. Some alternatives to coal energy could be using oil, gas and even atomic energy in some cases.
Japan bombed Hawaii. (pearl harbor)
By B-29 Superfortresses using Norden Bombsight.