SAT Subject Physics Practice Question 236: Answer and Explanation
7. In which type of decay is the identity of the nucleus unchanged?
A. Alpha decay
B. β– decay
C. β+ decay
D. Electron capture
E. Gamma decay
Correct Answer: E
A nucleus in an excited energy state can “relax” to a lower energy state by releasing energy. If the photon(s) emitted in this process are in the gamma-ray portion of the electromagnetic spectrum, we refer to this “decay” as gamma decay. The numbers of protons and neutrons remain unchanged.