Of the total incident solar radiation the proportion of PAR is
Of the total incident solar radiation the proportion of PAR is
about $60 \%$
less than $50 \%$
more than $80 \%$
about $70 \%$
Solution
PAR (Photosynthetically active radiation) designates the spectral range of solar radiation from 400 to $700 \mathrm{~nm}$ that photosynthetic organisms are able to use in the process of photosynthesis. Of the total incident solar radiation the proportion of PAR is less than $50 \%$.