Question

The total solar radiation proportion of PAR is

• A. Less than 50%
• B. More than 80%
• C. About 70%
• D. About 60%

Answer 1

Answer: (A)

Less than 50%

Sunlight is like a rain of photons of different frequencies. Visible light consists of radiations having a wavelength of 390-760 nm. Part of spectrum used in photosynthesis has a wavelength of 400-700 nm. It is called photosynthetically active radiation (PAR). The proportion of PAR of the total solar radiation is less than 50%. Only 2-10% of PAR is captured by the plants.