Two black bodies at temperautre 400K and 500K are placed in an evacuated enclosure whose wall are at 300K . Find the ratio of their rates of cooling.

Two black bodies at temperautre 400K and 500K are placed in an evacuat

1.	Two black bodies at temperautre 400K and 500K are placed in an evacuated enclosure whose wall are at 300K . Find the ratio of their rates of cooling.
Answer» Solution :HEAT LOST per SECOND by radiation E = `bar(SIGMA)(T^(4)-T_(0)^(4))` Ratio of the rates of cooling= `E_(1)/E_(2)` `E_(1)/E_(2)=((T_(1)^(4)-T_(0)^(4)))/((T_(2)^(4)-T_(0)^(4))` `T_(1)=400K, T_(2) = 500K, T_(0)= 300K` `E_(1)/E_(2)=(400^(4)-300^(4))/(500^(4)-300^(4))` `E_(1):E_(2)=175:544`