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 units will be

Step-by-step solution

Key Idea Apply Stefan's law of radiation. aligned E & = T ^4 E ₁ E ₂ & = [ T ₁ ~T ₂ ]^4 E ₂ & =7 [ 273+727 273+227 ]^4 & = ( 1000 500 )^4 7 & =112 cal - cm ⁻² ~s ⁻¹ aligned