Question

21. When does a nuclear fission reaction occur? A. When a nucleus is cut in two using a really sharp knife. B. When two nuclei collide and combine to one. C. When a large nucleus spontaneously is divided for no apparent reason. D. When the electric forces within the nucleus are stronger than the nuclear forces.

Answer 1

C

Step-by-step explanation:

It's not A because you can't use a knife to cut an atom nucleus. Its size is not perceptible to the eye.

It's not B because when two nuclei collide and combine into one, it's call fusion.

It's not D because you can't have stronger forces than the ones holding the nucleus together.

The correct answer is C.

To fission, the nucleus needs to have at least two things: critical mass (only big ones can fission spontaneously) and instability (incorporate a neutron ).