Question

The fission of uranium-$235$ by means of slow-moving neutrons is called a/an

• A. Chain reaction
• B. Irreversible chemical reaction.
• C. Explosion
• D. None of these

Answer 1

The correct option is A

Chain reaction

1. The process of splitting a heavy nucleus into two or smaller nuclei is called nuclear fission.
2. When a slow-moving neutron strikes U-$235$, fission takes place and it produces fast neutrons.
3. These fast neutrons will be slowed down in the moderator and again converted into slow neutrons.
4. Again with these slow neutrons, fission continues and this process is called a nuclear chain reaction.
5. Therefore, when a slow neutron strikes the U-$235$, it undergoes a chain reaction.

Hence, option A is the correct answer.