Half-life
Core concepts and learning points for this section:
Syllabus Points
Core
- 5.2.4.1 Define the half-life of a particular isotope as the time taken for half the nuclei of that isotope in any sample to decay; recall and use this definition in simple calculations, which might involve information in tables or decay curves (calculations will not include background radiation)
Supplement
- 5.2.4.2 Calculate half-life from data or decay curves from which background radiation has not been subtracted
- 5.2.4.3 Explain how the type of radiation emitted and the half-life of an isotope determine which isotope is used for applications including: (a) household fire (smoke) alarms (b) irradiating food to kill bacteria (c) sterilisation of equipment using gamma rays (d) measuring and controlling thicknesses of materials with the choice of radiations used linked to penetration and absorption (e) diagnosis and treatment of cancer using gamma rays www.cambridgeinternational.org/igcse 36 Subject content