Question

Study the figure which shows the effect of light on the rate of photosynthesis. Based on the graph, what do C and D represent on the curve?

• A. C represent that at lower light intensity there is no further decrease in photosynthesis and other factors become limiting. D represents the minimum light intensity which can affect the rate of photosynthesis.
  
• B. C represents the maximum light intensity which can affect the rate of photosynthesis. D represent that at higher light intensity there is no further increase in photosynthesis and other factors become limiting.
• C. C represent that at higher light intensity there is no further increase in photosynthesis and other factors become limiting. D represents the maximum light intensity which can affect the rate of photosynthesis.
• D. None of the above.

Answer 1

The correct option is C C represent that at higher light intensity there is no further increase in photosynthesis and other factors become limiting. D represents the maximum light intensity which can affect the rate of photosynthesis.

Low light intensity lowers the rate of photosynthesis. As the intensity is increased the rate also increases. However, after reaching an intensity of 10,000 lux (lux is the unit for measuring light intensity) there is no effect on the rate. Very high intensity may, in fact, slow down the rate as it bleaches the chlorophyll. Normal sunlight (usually with an intensity of about 100,000 lux) is quite sufficient for a normal rate of photosynthesis. On graph, C represent that at higher light intensity there is no further increase in photosynthesis and other factors become limiting. D represents the maximum light intensity which can affect the rate of photosynthesis.

Therefore, the correct answer is option C.