Equal masses of barley leaves are illuminated at the same light intensity and temperature. Oxygen volumes are measured at two carbon dioxide concentrations. Each of the three measurements at 0.04% carbon dioxide lasts 5 minutes; each measurement at 0.08% lasts 6 minutes.
| Carbon dioxide concentration in % | First volume in cm3\text{cm}^3cm3 | Second volume in cm3\text{cm}^3cm3 | Third volume in cm3\text{cm}^3cm3 |
|---|---|---|---|
| 0.04 | 5.4 | 5.7 | 5.1 |
| 0.08 | 8.4 | 8.7 | 8.1 |
What is the ratio of the mean rate at 0.08% carbon dioxide to the mean rate at 0.04% carbon dioxide?
1.56
1.87
0.77
1.30
87 exam-style questions on Edexcel GCSE Biology 6.1 Photosynthesis, covering 6.1.1 Photosynthetic organisms as producers, 6.1.2a Limiting factors on the rate of photosynthesis, 6.1.2b Interactions of limiting factors on photosynthesis, and 6.1.3 Inverse square law and light intensity. Each one has a worked solution and a mark scheme showing where the marks go.