What happens during photosynthesis? - OCR 21st CenturyEffect of light intensity on photosynthesis

What is photosynthesis? Use this GCSE OCR Science study guide to revise what type of reaction photosynthesis is, as well as factors affecting enzyme action and the effect of chlorophyll on photosynthesis.

Part ofCombined ScienceLiving together - Food and ecosystems

Scientific calculations - effect of light intensity on photosynthesis

The table shows a set of results obtained by students investigating the effect of light intensity on photosynthesis. They varied the distance of the plant from the light source.

Distance from light source (cm)Rate of photosynthesis (bubble per min)
10120
1554
2030
2517
3013
Distance from light source (cm)10
Rate of photosynthesis (bubble per min)120
Distance from light source (cm)15
Rate of photosynthesis (bubble per min)54
Distance from light source (cm)20
Rate of photosynthesis (bubble per min)30
Distance from light source (cm)25
Rate of photosynthesis (bubble per min)17
Distance from light source (cm)30
Rate of photosynthesis (bubble per min)13

If we draw a graph of this data:

A graph showing the number of bubbles produced per minute.

Note that this graph is a curve.

Question

From the graph, suggest the rate of oxygen production when the light source is at 18 cm.