Paper 2 Nuclear Physics Drills

Q1 Nuclear Decay Equation

A nucleus ${}_{83}^{214}\mathrm{Bi}$ undergoes beta-minus decay.

1. Write the beta-minus decay equation using conservation of nucleon number and charge. [2]
2. State what happens to a neutron in beta-minus decay. [2]
3. Explain why the neutrino was proposed in beta decay. [2]

Q2 Half-life and Background

A detector records $620\mathrm{counts}\mathrm{mi}{\mathrm{n}}^{-1}$ from a source plus background. Background is $40\mathrm{counts}\mathrm{mi}{\mathrm{n}}^{-1}$. After $18\min$ the source plus background count rate is $112.5\mathrm{counts}\mathrm{mi}{\mathrm{n}}^{-1}$.

1. Calculate initial corrected source count rate. [1]
2. Calculate final corrected source count rate. [1]
3. Determine the half-life. [3]

Q3 Binding Energy

The mass defect of a nucleus is $3.20\times 10^{-28}\mathrm{kg}$.

1. Calculate the binding energy in joules. [2]
2. Explain why binding energy per nucleon is useful. [2]
3. State why energy is released in fission using the binding-energy curve. [2]