Question

Rate of photosynthesis is higher in

• A. Very high light
• B. Red light
• C. Green light
• D. Continuous light

Answer 1

The correct option is B Red light

Light is an essential factor for photosynthesis. There is a linear relationship between incident light and $C{O}_2$ fixation at low light intensities. At higher light intensities, gradually the rate does not show further increase as other factors become limiting. Light between 400-700 nm wavelength constitute the photosynthetically active radiation (PAR). Red light is absorbed maximum by chlorophyll. So, the rate of photosynthesis is higher in the red light of the visible spectrum. The wavelength of light least effective in photosynthesis is green because plants themselves are green due to the pigment Chlorophyll. So, the rate of photosynthesis is minimum in green light.