Question

Maximum photosynthesis occurs in
(a)Blue light
(b)Red light
(c)Green light
(d)White light

Answer 1

In the wavelength area of more than 620 nm, maximum photosynthesis occurs. The corresponding light is denoted by the color in this range. This color belongs to VIBGYOR. In traffic lights, this color denotes the stop sign.

Complete answer:
Visible portions of radiation are absorbed by photosynthetic pigments. Typically, in blue and red light, plants exhibit a high rate of photosynthesis. In red light, maximum photosynthesis was observed, rather than in blue light. The minimal effect was observed in green light.
Photosystem II, which is membrane-bound, absorbs light. For blue light, maximum absorption is observed. Thus, in red light, full photosynthesis occurs.

Additional Information: -When a plant is given monochromatic light (single light color), the highest absorption of blue light is seen, but the highest photosynthesis rate is seen in red light.
-This is because red light is absorbed by the membrane-bound photosystem II. On the other side, chlorophyll and carotenoids absorb blue light, although certain carotenoids are not found in chloroplasts.
-Carotenoids are made up of carotenes and xanthophylls, where the carotenes do not transfer the absorbed energy to chlorophyll as effectively.
-Therefore, some portion of the absorbed light falling under blue is not transferred to photosynthesis, while chlorophyll absorbs and efficiently uses all of the red light. In order to absorb the blue color of light in the greatest quantity, the maximum intensity of photosynthesis occurs in red light.
So, the correct answer is, ‘Red light’.

Note: Chlorophyll is a green-colored pigment that in plants absorbs light for photosynthesis. It is known as the primary pigment and is available in two forms: chlorophyll a and chlorophyll b. Between the wavelengths of 450-475 nm and 650-675 nm, chlorophylls absorb maximum light.