Consider the Sun to be a black body at temperature `T_(S) = 5780 K`. Radius of the Sun is `r_(S) = 6.96 xx 108 m`. The Earth - Sun distance is `R = 1.49 xx 1011m`. Assume that `30%` of the solar radiation that hits the earth is scattered back into space without absorption.
(a) Calculate the steady state average temperature of the earth assuming it to be a black body. Take `(0.7 )^((1)/(4))= 0.91`
(b) We know that average temperature of earth is `~=288K`. How does this value compare with that obtained in (a)? The difference is due to greenhouse effect. Comment on the following statement - “Emissivity of earth is reduced more than absorptivity due to green house effect.”
