If the temperature of the Sun were to increase from T to 2T and its radius from R to 2R. The ratio of radiant energy received on earth to what it was previously will be . . . .. . .

Options

A. 4
B. 16
C. 32
D. 64

Answer

D

Explanation

The amount of radiant energy, `W=esigmaAT^(4)` (Stefan-Boltzmann.s law)
`W=e sigma(4piR^(2))T^(4)(becauseA=4piR^(2))`
`WpropR^(2)T^(4)`
`:.(W_(2))/(W_(1))=((R_(2))/(R_(1)))^(2)((T_(2))/(T_(1)))^(4)`
`=((2R)/(R))^(2)((2T)/(T))^(4)`
`=4xx16=64`