Radioactive phosphorus-32 emits β\betaβ-particles and has a half-life of 14 days. It decays to produce sulfur-32. Which statement about this decay is correct?
After 14 days no more β\betaβ-particles are emitted.
After 14 days the number of sulfur-32 atoms has halved.
After 28 days the phosphorus-32 has decayed completely.
After 28 days the number of phosphorus-32 atoms has reduced to one quarter of its initial value.
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.