A hospital compares three X-ray settings. Image quality must be at least 7, and patient exposure must be as low as possible.
| Setting | Image-quality score | Relative patient exposure |
|---|---|---|
| P | 5 | 2 |
| Q | 7 | 4 |
| R | 9 | 9 |
Which recommendation meets these requirements?
Use Q because it meets the quality threshold with less exposure than R.
Use P because it gives the lowest exposure despite its lower quality.
Use R because its higher quality means that it causes less cell damage.
Use Q because reaching the quality threshold removes the risk of mutation.
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.