During a wildlife survey, a researcher first examines an insect under a bright lamp. The researcher then switches off the lamp and looks at an animal further away.
| object viewed | distance from eye in m | light intensity at eye in lux | pupil diameter in mm |
|---|---|---|---|
| insect | 0.15 | 1200 | 2.4 |
| animal | 12 | 30 | 5.7 |
Calculate the percentage increase in pupil diameter when the researcher looks at the animal.
Explain how the changes in the iris and lens help the researcher to see the animal.
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.