Explain why prolonged exposure to ultraviolet radiation is considered more hazardous to human health than prolonged exposure to infrared radiation of the same intensity.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Different types of electromagnetic radiation interact with the human body in different ways. Some types are used in medical and industrial applications, whilst others pose significant health risks.
Model answer (4 marks)
Ultraviolet (UV) radiation has a higher frequency than infrared (IR) radiation.
Because frequency is higher, each UV photon carries more energy than an IR photon.
The greater photon energy allows UV to break chemical bonds in DNA and other cellular molecules, causing surface‑cell damage and mutations that can lead to skin cancer.
IR photons lack sufficient energy to break these bonds; they mainly raise the temperature of skin, producing burns but not cellular mutations.
Because frequency is higher, each UV photon carries more energy than an IR photon.
The greater photon energy allows UV to break chemical bonds in DNA and other cellular molecules, causing surface‑cell damage and mutations that can lead to skin cancer.
IR photons lack sufficient energy to break these bonds; they mainly raise the temperature of skin, producing burns but not cellular mutations.
Examiner tips
- State the frequency difference first, then link to photon energy, then to biological effect, finally contrast with IR.
- Use terms: frequency, photon energy, DNA damage, mutation, skin cancer, burns.
- Keep answer concise and structured in points.
Common mistakes
- Confusing wavelength with energy; forgetting to mention photon energy.
- Over‑explaining IR effects or mentioning non‑relevant effects such as eye damage.
- Using vague phrases like ‘more harmful’ without explaining the mechanism.
Mark scheme (4 marks)
- Ultraviolet radiation has a higher frequency than infrared radiation
- Higher frequency means ultraviolet radiation carries more energy (per wave / photon)
- Ultraviolet radiation can cause damage to surface cells and eyes / can cause mutations in cells
- Infrared radiation only causes skin burns / does not have sufficient energy to cause cell mutation or cancer
Key terms in this question
ultraviolet · infrared radiation
Related
- All Edexcel GCSE Physics (1PH0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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