This pack covers AQA specification 6.4.2.1: unstable nuclei and the random process of radioactive decay, activity in becquerel and count-rate measured by a detector, what alpha particles, beta particles, gamma rays and neutrons are, the penetration, range in air and ionising power of alpha, beta and gamma radiation, and how to choose the best source of radiation for a use.

The Topic Mastery Sheet gives the AQA statements on unstable nuclei, activity and count-rate, with a table comparing the two and a worked example turning the number of nuclei decaying each second into an activity in kBq. A table sets out what each type of nuclear radiation is in AQA wording, and an exam tip explains what ‘describe’ means for these questions, quoting the June 2025 examiners’ report. An original diagram shows what stops alpha, beta and gamma radiation, with a table of penetration, typical range in air and ionising power. Four question cards and a table of uses for alpha, beta and gamma sources show how to choose a source. A key vocabulary table gives the exact AQA terms, six common errors are corrected, and the Grade 8-9 stretch section explains why the best source for a thickness gauge depends on the thickness of the material.

The Student Exam Practice Sheet (22 marks) has five questions. They progress from tick-box items on activity and radioactive decay and naming the fourth type of nuclear radiation, through identifying alpha, beta and gamma sources from an absorber table and explaining why alpha particles have a short range in air, to a smoke alarm question on why an alpha source is suitable and what an activity in kBq means. A question on a paper thickness gauge asks students to read a count-rate graph and explain the change and why gamma would not work, and the sheet ends with a 6-mark question explaining why gamma, and not alpha or beta, is used to sterilise sealed medical equipment, marked by levels. Questions are numbered and marked in AQA style (01.1, [2 marks], Tick (✓) one box). The answer key follows AQA mark-scheme conventions (allow, ignore, do not accept, dependent marks) and gives the AO and specification reference for every part; the 6-mark question uses AQA’s own level descriptors.

Project the mastery sheet for a ready-made revision lesson, set the practice sheet as homework or a timed check, or use the pack for intervention and independent study. PDF and editable Word versions are both included. Written for AQA GCSE Combined Science: Trilogy (8464); content that appears only in AQA GCSE Physics (8463) is not included. All questions are original. This resource is not endorsed by or affiliated with AQA.

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