At `273^(@)C` ,the emissive power of a perfect black body is R . What is its value `0^(@)C` ?

Options

A. `(R)/(4)`
B. `(R)/(16)`
C. `(R)/(2)`
D. None of these

Answer

B

Explanation

From Stefan's law, the total radiant energy emitted per second per unit surface area of a black body is proportional to the fourth power of the absolute temperature (T) of the body. `therefore" "E=sigmaT^(4)`
where, `sigma` is Stefan's constant.
Given, `E_(1)=R_(1)T_(1)=273^(@)C=273+273=546K`
`T_(2)=0^(@)C=273K`
`therefore" "(E_(1))/(E_(2))=(T_(1)^(4))/(T_(2)^(4))`
`rArr" "E_(2)=(T_(2)^(4))/(T_(1)^(4))E_(1)=((272)^(4))/((546)^(4))R=(R)/(16)`