Question

Maximum absorption by chlorophyll-a is seen in (P). The maximum rate of photosynthesis is seen in (Q). The correct words filling (P) and (Q) are

• A. (P): red light and (Q): red light
• B. (P): blue light and (Q): blue light
• C. (P): blue light and (Q): red light
• D. (P): red light and (Q): blue light

Answer 1

Answer: (C)

If we observe the absorption spectrum of chlorophyll-a, there is a large peak in the blue region while a smaller peak in the red region. Thus, maximum absorption by chlorophyll-a is seen in blue light. If we observe the action spectrum, we see that the maximum rate of photosynthesis is seen in red light. Thus, red light is better for photosynthesis.