The atomic mass of an atom remains the same after gamma radiation
true
false

It all depends.

-- If the atom absorbed or emitted the radiation, then False.

-- If the radiation came, passed through the atom, and went, then True.

You only said "after gamma radiation" which, you'll have to admit, is pretty vague.

True

Explanation:

I think the statement is in fact The atomic mass of an atom remains the same after gamma irradiation. That means an atom has been exposed to gamma radiation. The result will depend on the strength of gamma ray and how heavy the original atom is. In most cases, the gamma ray is not very strong and the original atom is not radioactive, then the atomic mass will remain the same.