GCSE Physics: Uses and Hazards of Radiation, Fission and Fusion

This material follows on from the basics of radioactive decay and looks at what nuclear radiation is used for, how its risks are judged, and how energy is released from the nucleus. These topics are part of separate (triple) GCSE Physics, for example in AQA's specification, and are regularly examined through longer explain-and-evaluate questions.

The first part is about radiation in everyday life. You identify natural sources of background radiation, such as radon gas from rocks like granite and cosmic rays, and man-made ones, such as fallout from weapons testing and nuclear accidents and medical procedures, and explain why the dose a person receives depends on where they live and what job they do. Radiation dose is measured in sieverts or millisieverts, and you compare doses with simple arithmetic. You also explain how the half-life of a source affects how long it stays hazardous.

The second part is about choosing the right radiation for a job. A medical tracer must be a gamma emitter with a short half-life: alpha would cause damage inside the body and could not be detected outside it. Radiotherapy has to kill cancer cells while limiting damage to healthy tissue. Industrial and household uses match penetrating power to the task: gamma for sterilising packaged instruments, beta for monitoring the thickness of paper, alpha in smoke alarms. A half-life calculation shows how quickly a tracer's activity falls.

The final part covers nuclear fission and fusion. In fission a large unstable nucleus such as uranium-235 absorbs a neutron and splits into two smaller nuclei, releasing two or three neutrons, gamma rays and energy; the released neutrons can cause a chain reaction, controlled in a reactor and uncontrolled in a nuclear weapon. In fusion two light nuclei join to form a heavier one and some mass is converted to energy, which is how the Sun shines. You explain why fusion needs extremely high temperatures and pressures and why it is not yet used in commercial power stations.

The material offers three formats. The quiz has 12 questions mixing single-answer and multiple-answer items, each with an explanation. The flashcards give quick revision of the key definitions. The written work is a printable sheet of 8 longer questions, including choosing a tracer from a set of isotopes, half-life and dose calculations, and extended comparisons of fission and fusion, which you answer by hand and upload for feedback on each answer.

• Identify natural and man-made sources of background radiation and explain why the dose received varies
• Use radiation dose in sieverts and millisieverts to compare risks
• Explain how half-life affects the hazard from a source and calculate the activity remaining
• Choose a suitable radiation and half-life for medical tracers, radiotherapy, sterilising and thickness monitoring
• Describe nuclear fission and explain how a chain reaction happens and is controlled
• Describe nuclear fusion and explain why it needs very high temperatures and pressures

Practice material written by Zestly, based on the DfE GCSE physics subject content (atomic structure: hazards and uses of radioactive emissions and of background radiation; nuclear fission and fusion), with AQA GCSE Physics 8463 used as the example specification. Dose figures in the questions are illustrative.