Depends on the exact bomb:
Basically pick any size you want as required by your application, a nuclear bomb can probably be made in that diameter.
Yes, nuclear bombs utilize nuclear energy. They rely on the process of nuclear fission or fusion to create an explosive release of energy.
A nuclear bomb is a generic term for any explosive device that relies on nuclear reactions to produce a large amount of destructive force, while an atomic bomb specifically refers to a type of nuclear bomb that relies on nuclear fission reactions to release energy. Therefore, all atomic bombs are nuclear bombs, but not all nuclear bombs are atomic bombs.
Nuclear bombs can use either nuclear fission or nuclear fusion as the primary mechanism of energy release. Most nuclear bombs in current arsenals rely on nuclear fission reactions, while thermonuclear bombs use a fission reaction to trigger a fusion reaction.
The Big Bang event involved an immense amount of energy, estimated to be equivalent to the explosion of billions of nuclear bombs.
Yes, nuclear bombs produce gamma radiation as a result of the nuclear fission or fusion reactions that release high-energy photons. Gamma radiation is a form of electromagnetic radiation that accompanies the explosion of nuclear devices.