Explain how the type of radiation emitted and the half-life of the 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

Explain how radioactive materials are moved, used and stored in a safe way, with reference to: (a) reducing exposure time (b) increasing distance between source and living tissue (c) use of shielding to absorb radiation