The radiant energy from the Sun incident normally at the surface of earth is `20kcal//m^(2)` min What would have been the radiant energy incident normally on the earth if the sun had a temperature twice of the present one ? .

Options

A. 160 kcal/`m^(2)` min
B. 40 kcal/`m^(2)` min
C. 320 kcal/`m^(2)` min
D. 80 kcal/`m^(2)` min

Answer

C

Explanation

`(E_(2))/(E_(1))=((T_(2))/(T_(1)))^(4)=(2)^(4)=16`
`E_(2)=16xx20=320kcal//m^(2)` min.