Understand that some atomic nuclei are unstable and emit radiation as they transition to a more stable state, defining this random process as radioactive decay.
Define activity as the rate at which a source of unstable nuclei decays, and recognize the becquerel (Bq) as its unit of measurement.
Define count-rate as the number of decays recorded per second by a detector.
Describe the composition and fundamental properties of alpha particles (two neutrons and two protons, equivalent to a helium nucleus), beta particles (a high-speed electron ejected from the nucleus), gamma rays (electromagnetic radiation from the nucleus), and neutron emission.
Compare alpha particles, beta particles, and gamma rays in terms of their penetration through materials, range in air, and ionising power.
Apply knowledge of radiation properties to evaluate and select the most appropriate radiation sources for specific practical applications.
