Which statement about radioactive decay is correct?
The rate of decay of a radioactive sample can be decreased by cooling it to a very low temperature.
It is impossible to predict which specific nucleus in a sample will decay next.
The half-life of a radioactive isotope depends on the initial number of undecayed nuclei.
A radioactive sample decays completely to zero activity after exactly two half-lives.
484 exam-style questions on CIE IGCSE Physics 5.2 Radioactivity, covering 5.2.1 Background radiation and measuring count rate, 5.2.2a Alpha, beta and gamma emission, 5.2.2b Deflection and ionising effects of nuclear radiation, 5.2.3a Radioactive decay, 5.2.3b Effects of decay on the nucleus and decay equations, 5.2.4a Half-life, 5.2.4b Choosing isotopes for applications, and 5.2.5 Effects of ionising radiation and safety precautions. Each one has a worked solution and a mark scheme showing where the marks go.