A black body at a hot temperature of `227^(@)C` radiates heat at a rate of `10" cal cm"^(-2)" s"^(-1)`. At a temperature of `727^(@)C` the rate of heat radiated per unit area in cal `cm^(-2)s^(-1)` will be

Options

A. 200
B. 160
C. 250
D. 400

Answer

A

Explanation

`(E_(2))/(E_(1))=((T_(2))/(T_(1)))^(4)=((727+273)/(227+273))^(2)`
`(E_(2))/(E_(1))=(2)^(4)" "rArrE_(2)=10xx16`.
`rArrE_(2)=160"cal cm"^(-2)"sec"^(-1)`.
Thus correct choice is (b).