What do the WJEC radioactivity topics (2.7 to 2.9) cover?

Topic 2.7 Types of radiation covers the structure of the atom, alpha, beta and gamma radiation and their penetrating power and ionising ability, background radiation, and the uses and hazards of radiation. Topic 2.8 Half-life covers the random nature of decay, activity, half-life and decay curves with applications such as dating and medicine. Topic 2.9 Nuclear decay and nuclear energy covers nuclear decay equations, nuclear fission, the chain reaction, the reactor and nuclear fusion.

What are the penetrating powers of alpha, beta and gamma?

Alpha is the most ionising but least penetrating, stopped by a sheet of paper. Beta is moderately penetrating, stopped by a few millimetres of aluminium. Gamma is the least ionising but most penetrating, only reduced by thick lead or concrete. Because of their charge, alpha and beta are deflected in opposite directions by a magnetic field, while gamma is not deflected.

What is the difference between fission and fusion?

Nuclear fission is the splitting of a large nucleus, such as uranium-235, when it absorbs a neutron, releasing energy and more neutrons that drive a chain reaction; it is used in nuclear power stations. Nuclear fusion is the joining of two small nuclei, such as hydrogen, to form a heavier nucleus, releasing even more energy; it needs star-like temperatures and pressures and powers the stars.

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WJEC GCSE Physics radioactivity and nuclear energy overview

Q: How is the radioactivity topic examined?

It sits in Unit 2 (Forces, Space and Radioactivity), a 1 hour 45 minute written paper worth 80 marks and 45% of the GCSE. Expect questions on radiation properties and uses, half-life calculations and decay curves, balancing nuclear equations, and descriptions of fission, the chain reaction and fusion.

An overview of the radioactivity topics (2.7 to 2.9) in Unit 2 of WJEC GCSE Physics (3420), mapping types of radiation, half-life, and nuclear fission and fusion, with the key properties and how each part is examined.

Generated by Claude Opus 4.87 min readWJEC 3420 Unit 2.7-2.9Updated 2026-06-14

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The topics 2.7 to 2.9 content
How the radioactivity topic is examined
How to study the radioactivity topic
For the official specification

The radioactivity and nuclear energy topics (2.7 to 2.9) of WJEC GCSE Physics (specification 3420) are about the atom, the three types of nuclear radiation, half-life, and how energy is released by fission and fusion. They are examined in Unit 2 (Forces, Space and Radioactivity). This page maps the topics and links to a focused answer page for each part.

The topics 2.7 to 2.9 content

Types of radiation: The structure of the atom, alpha, beta and gamma radiation, their penetrating power and ionising effect, background radiation, and the uses and hazards of radiation. See Types of radiation.
Half-life: The random nature of decay, activity, half-life, reading half-life from a decay curve, and applications such as dating and medicine. See Half-life.
Nuclear fission and fusion: Nuclear decay equations, nuclear fission and the chain reaction, the nuclear reactor, and nuclear fusion. See Nuclear fission and fusion.

How the radioactivity topic is examined

These topics sit in Unit 2, a written paper of 1 hour 45 minutes, worth 80 marks and 45% of the GCSE, tiered into Foundation and Higher. Expect questions on radiation properties and uses, half-life calculations and decay curves, balancing nuclear equations, and descriptions of fission, the chain reaction and fusion.

How to study the radioactivity topic

Learn the three radiations. Know the nature, ionising power and penetration of alpha, beta and gamma.
Halve, do not divide. For half-life, halve the activity once per half-life.
Balance equations. Mass numbers and atomic numbers must match on both sides.
Separate fission and fusion. Fission splits a large nucleus; fusion joins small nuclei.
Link uses to properties. Choose a radiation or isotope by its penetration and half-life.

For the official specification

WJEC publishes the full specification, past papers and mark schemes at wjec.co.uk. Always revise from the current specification and WJEC's own past papers, because question style, tiering and the formula list are board-specific.

Sources & how we know this

WJEC GCSE Physics specification (3420) from 2016 — WJEC (2016)