Explain the uses of radioactivity in medicine, agriculture, industry and archaeology. What safety measures should be taken?

1. 1 · Open. Radioisotopes give out radiation that can be detected, so they are used as tracers and for treatment.
2. 2 · Medicine.
   • Cobalt-60: cancer treatment.
   • Iodine-131: goitre and other thyroid disorders.
   • Sodium-24: blood circulation.
   • Gamma rays: sterilising instruments.
3. 3 · Agriculture. P-32 traces fertiliser uptake; gamma rays preserve food and produce high-yield varieties.
4. 4 · Industry. Detecting leaks in pipes, cracks in castings and the thickness of sheets; uranium as fuel.
5. 5 · Archaeology. Carbon-14 dating finds the age of fossils, wood and bones.
6. 6 · Hazards and safety.
   • Hazards: burns, cancer, leukaemia, genetic disorders.
   • Safety: lead containers, lead aprons and gloves, long tongs, dosimeters.
7. 7 · Real-life link. Keeladi charcoal was carbon dated; cancer hospitals use cobalt-60.
8. 8 · Close. Used with care, radioactivity saves lives and helps science.

Scoring tip: Name the isotope with each use (Co-60, I-131, C-14): a use without its isotope gets only part of the mark.