Question

Which of the following is the least effective in photosynthesis?
(A) Red light
(B) Blue light
(C) Green light
(D) Violet

Answer 1

Hint: Green plants tend to reflect the colour in the luminous spectrum. In other words, the plant's chlorophyll absorbs the red and blue light even more readily than the green light.

Complete answer: Photosynthesis is the mechanism of transforming the light energy into chemical energy. Using the energy of light, the carbon dioxide and water, carbohydrates such as sugars is synthesised. The term photosynthesis is derived from the terms of Greek, photo for 'light' and synthesis meaning 'to bring together.' Chlorophyll, a photosynthetic pigment of the plant that absorbs light energy while air that contains carbon dioxide and oxygen enters the plant through the stomata of the leaves.

Now lets us find the solution from the given options-
1. Light travels in waves but are often called photons as small energy packets. A luminous photon comprises the whole visible spectrum: red, orange, yellow, green, blue, indigo, and purple. Plants absorb light wavelengths red, orange, yellow, blue, indigo, and violet but reflect green.
2. Blue light is the highest effective in photosynthesis.
In driving photosynthesis the green colour of light is the least influence. Photosynthetic pigments (chlorophyll) typically absorb visible light (wavelength: 380 to 740 nm), but do not absorb green light. This is because the green light is transmitted and reflected, rather than the chlorophyll absorbed.

Thus, the right answer is option C i.e., Green light

Note:Photosynthesis occurs more in rays of blue and red light, and less in rays of green light, or not at all. The light which is consumed the best is blue, so this shows the highest photosynthesis rate, after which red light comes. The plant cannot absorb green light, and therefore can not be used for photosynthesis.