Question

Out of the total sunlight energy reaching the atmosphere, the fraction utilized in photosynthesis is approximately:

• A. $0.002%$
• B. $0.02%$
• C. $0.2%$
• D. $2.0%$

Hint:

Despite being vital for life, photosynthesis uses only about \textbf{0.2%} of the total solar energy reaching the Earth.

Answer 1

The Correct Option is C

Step 1: A very large amount of solar energy reaches the Earth’s atmosphere.
Step 2: Only a small fraction of this energy is absorbed by plants for the process of photosynthesis.
Step 3: Of the total solar radiation:

Much is reflected back into space,
Much is absorbed as heat,
Only a tiny fraction is converted into chemical energy by plants.

Step 4: Experimental and ecological studies show that only about 0.2% of the sunlight energy reaching the atmosphere is ultimately utilized in photosynthesis.