Question

If the temperature of the sun were to increase form T to 2T and its radius from R to 2R, then the ratio of the radiant energy received on earth to what it was previously will be
A. `32`
B. `16`
C. `4`
D. `64`

Answer 1

Correct Answer - D
(d) `E=sigmaAT^4 , A prop R^2 :. E prop R^2T64`
`:. (E_2)/(E_1)=(R_2^2T_2^4)/(R_1^2T_1^4)`
`rArr (E_2)/(E_1)=((2R)^2(2T)^4)/(R^2T^4)=64`