Background Radiation and Uses of Radiation
Get to grips with Background Radiation and Uses of Radiation for GCSE Physics with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. A separate (triple) physics topic: background radiation comes from rocks, cosmic rays and medical sources, and radiation is used in medicine to diagnose and treat illness.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Background radiation is the radiation around us all the time, from natural and human-made sources. This is a Triple-only topic.
Natural sources include rocks, particularly granite which releases radon gas, and cosmic rays from space. Human-made sources include fallout from nuclear weapons testing and nuclear accidents. The level of background radiation varies with location and occupation — airline crew and radiographers receive higher doses.
Radiation dose is measured in sieverts, and one sievert is a large dose so millisieverts are often used. Uses of radiation include exploring internal organs using tracers, controlling or destroying unwanted tissue, and gamma sterilisation of medical equipment.
Revision notes
Sources of background radiation
Natural: rocks, especially granite which releases radon gas, and cosmic rays from space.
Human-made: fallout from nuclear weapons testing and from nuclear accidents. The level varies with location and with occupation.
Radiation dose
Dose is measured in sieverts, with 1000 millisieverts equal to 1 sievert.
Dose reflects the risk of harm from exposure. Airline crew receive a higher dose because cosmic radiation is greater at altitude, and radiographers receive higher doses from their work.
Uses of nuclear radiation
Exploring internal organs using radioactive tracers, which are followed with an external detector.
Controlling or destroying unwanted tissue, such as in cancer treatment. Sterilising medical equipment using gamma radiation, which kills microbes without heating.
Key points
- Background radiation is present all the time.
- Natural sources include rocks and cosmic rays.
- Granite releases radon gas.
- Human-made sources include weapons fallout.
- Dose is measured in sieverts.
- Radiation is used in tracers and sterilisation.
Worked examples
Example 1
Give two natural sources of background radiation. [2 marks]
Model answer
Rocks, particularly granite, which release radon gas (1 mark). Cosmic rays from space (1 mark).
Example 2
Explain why airline crew receive a higher radiation dose than most people. [2 marks]
Model answer
They spend long periods at high altitude (1 mark), where there is less atmosphere to absorb cosmic radiation, so the dose received is greater (1 mark).
Example 3
Explain why gamma radiation is used to sterilise medical equipment. [2 marks]
Model answer
Gamma radiation kills the microbes on the equipment (1 mark), and it can do so without heating the equipment, so items that would melt can still be sterilised (1 mark).
Common mistakes
Saying background radiation is only human-made.
Most of it comes from natural sources such as rocks and cosmic rays.
Giving the unit as becquerels.
Activity is in becquerels; dose is in sieverts.
Forgetting that background level varies.
It depends on location and occupation.
Not explaining why altitude matters.
There is less atmosphere to absorb cosmic radiation.
Exam tips
- Separate natural and human-made sources.
- Use sieverts for dose and becquerels for activity.
- Explain occupational differences through altitude or exposure.
- Remember this is a Triple-only topic.
Key terms
- Background radiation
- Radiation present around us at all times.
- Radon
- A radioactive gas released by granite.
- Sievert
- The unit of radiation dose.
- Tracer
- A radioactive substance used to follow processes in the body.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.