An experimentalist measures the radiation count rate from three distinct radioactive sources, PPP, QQQ, and RRR, using a Geiger-Müller (GM) tube connected to a counter. In order to identify the type of radiation emitted by each source, various absorbing materials are placed between the source and the GM window.
The measured count rates, in counts per minute (cpm), are recorded in the table below:
AbsorberNo source (background)Source PSource QSource RNone42850510720Thin sheet of paper3984651241Aluminium sheet (5 mm)414350839 \begin{array}{|l|c|c|c|c|} \hline \textbf{Absorber} & \textbf{No source (background)} & \textbf{Source } P & \textbf{Source } Q & \textbf{Source } R \\ \hline \text{None} & 42 & 850 & 510 & 720 \\ \hline \text{Thin sheet of paper} & 39 & 846 & 512 & 41 \\ \hline \text{Aluminium sheet (5 mm)} & 41 & 43 & 508 & 39 \\ \hline \end{array} AbsorberNoneThin sheet of paperAluminium sheet (5 mm)No source (background)423941Source P85084643Source Q510512508Source R7204139Based on these results:
Identify which source emits only alpha radiation and explain your choice.
Identify which source emits only beta radiation and explain your choice.
6 exam-style questions on AQA GCSE Physics 4.2 Atoms and nuclear radiation, covering 4.2.1 Radioactive decay and nuclear radiation, 4.2.2 Nuclear equations, 4.2.3 Half-lives and the random nature of radioactive decay, and 4.2.4 Radioactive contamination. Each one has a worked solution and a mark scheme showing where the marks go.