An experiment is set up to investigate the effect of light intensity on the rate of photosynthesis in Elodea. Initially, the light source is placed at a distance of 25 cm from the plant, and the light intensity is recorded as 180 arbitrary units180\text{ arbitrary units}180 arbitrary units.
The light source is then moved to a distance of 75 cm from the plant. What is the new light intensity received by the plant?
606060
202020
540540540
162016201620
12 exam-style questions on OCR GCSE Biology 1.4 Photosynthesis, covering 1.4.1 Photosynthesisers as biomass producers, 1.4.2 Factors affecting the rate of photosynthesis, and 1.4.3 Limiting factors in photosynthesis. Each one has a worked solution and a mark scheme showing where the marks go.