A radioactive nucleus of tritium decays to a nucleus of helium-3 by emitting a particle. Complete the nuclide equation to find the values of AAA and ZZZ, and state the name of particle X\text{X}X:
13H⟶ 23He+ ZAX ^{3}_{1}\text{H} \longrightarrow\ ^{3}_{2}\text{He} + \ _{Z}^{A}\text{X} 13H⟶ 23He+ ZAXA radiation detector in a laboratory records a reading of 15 counts/min15\text{ counts/min}15 counts/min. There are no experimental radioactive samples present in the laboratory. Explain why the detector records a reading and suggest one possible source.
Tritium has a half-life of 12 years12\text{ years}12 years. A fresh sample of tritium-labeled water in this laboratory gives a reading of 95 counts/min95\text{ counts/min}95 counts/min. An equivalent older water sample of the same volume and initial concentration gives a reading of 30 counts/min30\text{ counts/min}30 counts/min. It is suggested that the age of the older water sample is 24 years24\text{ years}24 years. Perform a calculation to check whether this suggestion is correct.
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.