The age of a meteorite rock sample can be estimated from rock samples containing rhenium (Re) and osmium (Os). 75187Re^{187}_{75}\text{Re}75187Re decays to 76187Os^{187}_{76}\text{Os}76187Os with a radioactive decay constant of 1.67×10−11 year−11.67 \times 10^{-11} \text{ year}^{-1}1.67×10−11 year−1.
Calculate, in years, the half-life of 75187Re^{187}_{75}\text{Re}75187Re.
A sample of this rock contains 2.35 mg2.35 \text{ mg}2.35 mg of 75187Re^{187}_{75}\text{Re}75187Re. Calculate the mass, in grams, of 75187Re^{187}_{75}\text{Re}75187Re that the rock sample contained when it was formed 4.12×1094.12 \times 10^94.12×109 years ago. Give your answer to an appropriate number of significant figures.
Calculate the activity, in Bq\text{Bq}Bq, of a sample of 75187Re^{187}_{75}\text{Re}75187Re of mass 2.35 mg2.35 \text{ mg}2.35 mg.
(Take the unified atomic mass unit u=1.661×10−27 kgu = 1.661 \times 10^{-27} \text{ kg}u=1.661×10−27 kg and 1 year=365 days1 \text{ year} = 365 \text{ days}1 year=365 days).
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.