Question

Which of the statements is/are true regarding gamma radiation?

• A. Gamma radiations can be a consequence of a nucleus transitioning from higher energy state to ground state.
• B. Gamma radiations are electromagnetic in nature.
• C. Gamma radiations are high energy electrons.
• D. Gamma radiations are high energy photons.

Answer 1

Answer: (A), (B), (D)

The correct options are
A Gamma radiations can be a consequence of a nucleus transitioning from higher energy state to ground state.
B Gamma radiations are electromagnetic in nature.
D Gamma radiations are high energy photons.

An alpha or beta decay leaves the daughter nucleus at an excited energy level, from which it spontaneously transitions to the ground state, releasing energy in a photon. Since the differences between these energy levels are of the order of MeV, the photons released carry very high energy. These photons constitute the gamma radiation that accompanies any gamma decay process.

For example, shown here is a ${}^{60}Co$ nucleus ${\beta }^{-}$ decaying into a ${}^{60}Ni$ (leaving the products with a net kinetic energy of 0.31 MeV), but leaving the nucleus at a high, excited energy level, from which it $\gamma$ decays twice (of photon energies 1.1732 MeV and 1.3325 MeV - very high!) to reach a much more relaxed, lower energy level.
Realize that each of these photons carries more energy than the mass-energy of an entire hydrogen atom - that's a lot of energy for one photon! Respect the gamma rays.