`""_(27)Co^(60)` is radioactive because

Radioactive ""_(27)^(60)Co is transformed into stable ""_28^60Ni by emitting two gamma - rays of energies

The radioactive isotope ""_(27)^(60)Co which is used in the teratment of cancer can be made by (n,p) reaction. For this reaction, the target nucleus is :

Using energy level diagram show emission of gamma rays by ""_(27)^(60)Co nucleus and subsequent beta decay to obtain ""_(28)^(60)Ni .