An atom bomb is based on the principle of

..The atomic bomb is mainly based on the principle of the Nuclear fission reaction. nuclear fission is a nuclear reaction  in which the nucleus of an atom splits into two or more smaller, lighter nuclei. An atom bomb needs a rapid reaction rate and exothermic reaction. The atomic reaction should trigger other atoms to go through the same. So, it needs a chain reaction. Compare the two types of atomic reactions to determine which one is best for an atom bomb.