Combined ScienceCode 5129
Half-life and uses of radioactive isotopes
What this topic asks you to be able to do
- Define half-life, for a specific isotope, as the length of time it takes for half of that isotope's nuclei in any sample to undergo decay.
- Explain how the kind of radiation an isotope emits and its half-life decide which isotope is chosen for uses including: (a) household fire (smoke) alarms (b) killing bacteria in food by irradiation (c) sterilising equipment with gamma rays (d) measuring and controlling thickness, where the radiation chosen depends on penetration and absorption (e) diagnosing and treating cancer with gamma rays