Of the total incident solar radiation the proportion of PAR is:

Options

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

Answer

C

Explanation

The source of energy in all ecosystem is solar energy. About 50% of the solar energy incident over earth is present in PAR (Photosynthetically active radiation). About 1-5% of Incident solar radiation or 2-10% of PAR is captured by the photosynthetic organisms in the synthesis of organic matter (gross primary producitivity).
Roughly 20% of it is consumed in respiration so that net capture of energy ( net primary productivity ) is 0.8-4% of incident radiation or 1.6-8% of PAR.