A black body, at a temperature of 227^ C , radiates heat at a rate of 20 cal m ⁻² ~s ⁻¹ . When its temperature is raised to 727^ C , the heat radiated by it in cal m ⁻² ~s ⁻¹ will be closest to

Step-by-step solution

The temperature of the black body is T₁=227^ C =500 ~K . Using Stefan's law, the rate of heat radiation per unit area per unit time is E₁= T^4 20= (500)^4 = 20 (500)^4 . Now the temperature of the blackbody is raised to T₂=727^ C =1000 ~K Rate of heat radiation per unit area aligned E₂ & = T₂^4= 20 (500)^4 (1000)^4 & =20 2^4=320 cal m ⁻² ~s ⁻¹ . aligned