A technician grows a tray of lettuce plants in an indoor growing unit. An instrument measures the volume of oxygen released by the plants.
The current performance of the plants and the minimum required performance are shown in the table.
| performance | distance from lamp in cm | volume of oxygen in cm3\mathrm{cm^3}cm3 | time in min |
|---|---|---|---|
| current | 60 | 18 | 6 |
| minimum required | — | 22 | 4 |
Light intensity is the only limiting factor at all the lamp positions being considered.
Two new lamp positions are proposed.
| proposal | distance from lamp in cm |
|---|---|
| A | 40 |
| B | 50 |
Evaluate the two proposed lamp positions to decide which should be used to meet the minimum required rate of photosynthesis.
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.