Question

Which light range is least effective in photosynthesis?

• A. Blue
• B. Green
• C. Violet
• D. Red

Answer 1

The correct option is B Green

Blue light:

Plants have accessory pigments such as carotenoid, xanthophylls , chlorophyll b. These pigments absorb light in the range of 420 nm - 425nm (blue light range) and transfer their energy to chlorophyll a for the conversion of light energy to chemical energy

Green light:

• Plants have different photosynthetic pigments, one of which is chlorophyll a.

• Chlorophyll a is a green pigment and it does not absorb green light of visible range rather it transmits and reflects green light.

• For this reason, photosynthesis is the least effective in green light.

Red light :

Chlorophyll a absorbs maximum light in the range of 600-700 nm and shows the highest rate of photosynthesis in the range of $600nm-0700$ nm,that is, red light.

Violet light :

Chlorophyll a shows its maximum absorption at $415$ nm (Violet light) and shows increased rate of photosynthesis in the violet range of light.

Final answer: Green