question_answer

If the temperature of the sun were to increase from T to 2T and its radius from R to 2R, then the ratio of the radiant energy received on the earth to what it was previously, will be                                             [AIEEE 2004]

A)  4                    

B)       16

C)  32                   

D)       64

Correct Answer: D

Solution :

[d] From Stefan's law, the energy radiated by the sun is given byassumingfor the sun.

In 1 st case,

In 2nd case,

The rate at which energy received at the earth is,

where,area of the earth,

distance between the sun and the earth.

So, In 1st case,