A worker in a nuclear power plant is required to handle equipment that may have been exposed to radioactive dust. Explain why wearing gloves and a face mask reduces the risk from radioactive contamination but does not fully protect against irradiation.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Radioactive contamination occurs when radioactive atoms are deposited on or enter the body, skin or clothing. Gloves and a face mask act as a physical barrier, preventing the dust from contacting the skin or being inhaled, so the amount of contamination is reduced.
Irradiation, however, is the exposure to ionising radiation emitted by a radioactive source. The body does not need to be in contact with the source for irradiation to occur. Penetrating radiation such as gamma rays can pass through the gloves and mask, so the worker can still receive a dose of radiation even though contamination is limited.
Irradiation, however, is the exposure to ionising radiation emitted by a radioactive source. The body does not need to be in contact with the source for irradiation to occur. Penetrating radiation such as gamma rays can pass through the gloves and mask, so the worker can still receive a dose of radiation even though contamination is limited.
Examiner tips
- Use the word ‘contamination’ to describe dust on skin, and ‘irradiation’ for radiation exposure. Explain the barrier function of gloves/mask for contamination. State that gamma rays can penetrate the barrier, giving irradiation. Keep the answer concise – 4 marks are enough for a short explanation.
Common mistakes
- Confusing contamination with irradiation. Failing to mention that gamma rays can penetrate the barrier. Using vague terms like ‘radiation’ without distinguishing contamination and irradiation.
Mark scheme (4 marks)
- Radioactive contamination involves radioactive atoms being transferred onto or into the body/skin/clothing
- Gloves and a face mask act as a physical barrier, preventing radioactive atoms from reaching the skin or being inhaled, so reducing contamination
- Irradiation is exposure to nuclear radiation emitted by a source; the object/person does not need to come into contact with the source
- Penetrating radiation (such as gamma rays) can pass through the gloves and mask, so irradiation of the body still occurs
Key terms in this question
radioactive contamination · irradiation
Related
- All AQA GCSE Physics (8463) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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