A student compares two exposure arrangements for the same ultraviolet lamp. In this model, the energy reaching the skin is proportional to intensity multiplied by exposure time. The table shows the arrangements.
| Arrangement | Relative intensity at skin | Exposure time in minutes |
|---|---|---|
| P | 4 | 3 |
| Q | 2 | 9 |
Which statement is correct?
P gives 1.5 times the exposure of Q and can damage surface cells.
Q gives 1.5 times the exposure of P and can damage surface cells.
Q gives 1.5 times the exposure of P and mainly heats internal cells.
P gives 1.5 times the exposure of Q and mainly heats internal cells.
104 exam-style questions on Edexcel GCSE Physics 5.4 Uses and dangers of EM radiation, covering 5.4.1 Dangers of electromagnetic radiation, 5.4.2 Uses of electromagnetic radiation, 5.4.3 Radio waves and oscillations in circuits, and 5.4.4 Changes in atoms and nuclei generating radiation. Each one has a worked solution and a mark scheme showing where the marks go.