A performer is waiting in a dim backstage area. A bright spotlight is switched on and then switched off again. The diameter of one of the performer's pupils is measured at intervals.
| Measurement condition | Pupil diameter (mm) |
|---|---|
| Before the spotlight was switched on | 6.0 |
| 5 seconds after the spotlight was switched on | 2.1 |
| 10 seconds after the spotlight was switched off | 4.3 |
| 30 seconds after the spotlight was switched off | 5.8 |
Explain why the pupil diameter changes after the spotlight is switched off. Suggest the pupil diameter 60 seconds after the spotlight is switched off.
102 exam-style questions on Edexcel GCSE Biology 2.4 The eye, covering 2.4.1 Structure and function of the eye and 2.4.2 Eye defects and their correction. Each one has a worked solution and a mark scheme showing where the marks go.