Spec 8463
Revise AQA GCSE Physics 4.2 Atoms and nuclear radiation with the question bank and revision guides.
Some atomic nuclei are unstable. The nucleus gives out radiation as it changes to become more stable. This is a random process called radioactive decay. • Activity is the rate at which a source of unstable nuclei decays. Activity is measured in becquerel (Bq) • Count-rate is the number of decays recorded each second by a detector (eg Geiger-Muller tube).
