Copper-66 is a radioactive isotope. As a nucleus of copper-66 decays, the emitted radiation includes a $\beta^-$ particle and a $\gamma$-ray photon. The count rate from a sample of copper-66 is determined with a detector and counter, as shown in Fig. 13.1.
(a)[3]
State three reasons why the activity of the copper-66 sample is not the same as the measured count rate.
(b)[2]
Over a time interval of $42.0$ minutes, the count rate from the copper-66 sample falls from $3.62 \times 10^{4}\,\text{Bq}$ to $1.21 \times 10^{2}\,\text{Bq}$. Calculate the half-life of copper-66.
(c)[1]
The $\gamma$-ray photons emitted by radioactive nuclei have particular energies, depending on the nucleus producing them. By comparison with emission line spectra, suggest what can be inferred about energy levels in nuclei.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Ambient background radiation” …