The difference between a nuclear reactor and an atomic bomb is that

1. no chain reaction takes place in nuclear reactor
2. the chain reaction in nuclear reactor is controlled
3. the chain reaction in nuclear reactor is not controlled
4. no chain reaction takes place in atomic bomb

Explanation

Option (b) is correct

• A nuclear reactor sustains a fission chain reaction in a controlled manner, regulating the rate of energy release through moderators and control rods that absorb neutrons. It relies on delayed neutrons and built-in safety systems to maintain stable, steady power generation. In contrast, an atomic (fission) bomb is designed for an uncontrolled, rapid chain reaction, achieving a supercritical state that releases enormous energy within a fraction of a second, without mechanisms to regulate or moderate the reaction.

Answer: (b) the chain reaction in nuclear reactor is controlled