An environmental monitoring team tracks two radon isotopes, Isotope X\text{Isotope } XIsotope X and Isotope Y\text{Isotope } YIsotope Y, which have half-lives of 16 minutes16\text{ minutes}16 minutes and 48 minutes48\text{ minutes}48 minutes, respectively. Freshly collected samples of both isotopes begin decaying at the same time. After a period of 96 minutes96\text{ minutes}96 minutes, both samples are measured to contain exactly the same number of active, undecayed nuclei. If the sample of Isotope Y\text{Isotope } YIsotope Y initially contained N0 N_0\,N0 nuclei, what was the initial number of nuclei in the sample of Isotope X\text{Isotope } XIsotope X?
116N0\frac{1}{16} N_0161N0
4N04 N_04N0
16N016 N_016N0
64N064 N_064N0
128 exam-style questions on AQA A Level Physics Radioactivity (A-level only), covering Rutherford scattering (A-level only), $\alpha$ , $\beta$ and $\gamma$ radiation (A-level only), Radioactive decay (A-level only), Nuclear instability (A-level only), Nuclear radius (A-level only), Mass and energy (A-level only), Induced fission (A-level only), and Safety aspects (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.