The splitting of an atom’s nucleus into two smaller nuclei is called
a. nuclear fusion.
b. nuclear fission.
c. a chain reaction.
d. a meltdown.

Option (b) is the correct answer.

Explanation:

When a large nuclei of an atom splits into two smaller nuclei then this type of reaction is known as nuclear fission.

For example,

Fission is a nuclear reaction and there is also release of energy during this reaction.

Thus, we can conclude that the splitting of an atom’s nucleus into two smaller nuclei is called nuclear fission.

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