(a)[1]
State the meaning of the term photon.
(b(i))[2]
Indium-123 ($^{123}_{49}\text{In}$) is radioactive. A nucleus of indium-123 emits a $\gamma$-ray photon with energy $1.1\,\text{MeV}$. Determine, for this $\gamma$-radiation, the frequency.
(b(ii))[2]
Indium-123 ($^{123}_{49}\text{In}$) is radioactive. A nucleus of indium-123 emits a $\gamma$-ray photon with energy $1.1\,\text{MeV}$. Determine, for this $\gamma$-radiation, the momentum of a photon.
(c)[2]
The indium-123 nucleus is stationary before the $\gamma$-ray photon is emitted. Use your answer in (b)(ii) to estimate the recoil speed of the nucleus after the photon is emitted.