A sample of a radioactive isotope is undergoing decay. Which of the following statements correctly describes this decay process?
Radioactive decay is random and spontaneous, meaning it is impossible to predict which specific nucleus will decay next.
The oldest nuclei in the sample are always the first to decay.
External factors such as temperature or pressure can be used to speed up the decay of the nuclei.
The nuclei at the surface of the sample will decay first because they are less shielded.
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.