A black body at `227^(@)C` radiates heat at the rate of `7 cal cm^(-2) s^(-1)`. At a temperature of `727^(@)C`, the rate of heat radiated in the same unit will be

Options

A. 60
B. 50
C. 112
D. 80

Answer

C

Explanation

Apply Stefan 's law of radiations ,
`therefore" "E=sigmaT^(4)`
Where, `sigma` is Stefan's constant
`Given, E_(1)=R,T_(1)=273^(@)C=273+273=546K`
`T_(2)=o^(@)C=273K`
`therefore " " (E_(1))/(E_(2))=(T_(1)^(4))/(T_(2)^(4))`
`rArr" " E_(2)=(T_(2)^(4))/(T_(1)^(4))E_(1)=(273)^(4)/(546)^(4)R=(R)/(16)`