A worker at a nuclear facility wears a photographic film badge at all times during their shift. Explain how the film badge is used to monitor the worker's exposure to radiation and why it is important to monitor this exposure.

Edexcel GCSE Physics (1PH0) — 6.1 Radioactivity · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Workers at nuclear facilities are required by law to wear personal radiation monitoring devices. One type of device uses photographic film.

Model answer (4 marks)

The film is exposed to the worker’s radiation field during the shift. When radiation passes through the film it ionises the silver halide crystals, producing a latent image that becomes visible as a darkening after development. The darker the film, the larger the dose of radiation the worker has received.

Radiation can damage cells and DNA, increasing the risk of cancer and other health problems. Therefore it is essential to monitor exposure so that the dose remains below the legal limits and to allow corrective action if the exposure is too high.

Examiner tips

  • Use the phrase ‘film darkens when exposed to radiation’ to show understanding of the mechanism.
  • Link the darkening to dose – greater darkening = higher dose.
  • Explain the health hazard (cancer, DNA damage) and the purpose of monitoring (stay below limits, take action).

Common mistakes

  • Confusing the film with a dosimeter that gives a numeric read‑out; the film only shows relative darkening.
  • Omitting the health hazard or the reason for monitoring; focusing only on the film’s behaviour.
  • Using vague terms like ‘radiation is bad’ without specifying cancer or DNA damage.

Mark scheme (4 marks)

  1. The film goes darker / is darkened when it absorbs radiation
  2. The greater the darkening of the film, the greater the amount / dose of radiation the worker has been exposed to
  3. Radiation is hazardous / harmful to the worker (e.g. can cause cancer / damage cells / damage DNA)
  4. Monitoring ensures the worker's exposure does not exceed safe limits / allows action to be taken if exposure is too high

Key terms in this question

photographic film badge · radiation

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