A sample contains 9600 undecayed nuclei of a radioactive isotope. The half-life of the isotope is 4 days.
Calculate the number of undecayed nuclei left in the sample after 16 days.
A factory needs a source to check the thickness of aluminium sheet as it is made. The source is placed above the sheet and the detector below it. Explain why a source that emits beta particles is used, and not a source that emits alpha particles or gamma rays.
40 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.