A Carnot's engine has an efficiency of 25 % when its sink is at 27^ C . If it has to be increased to 40 % , what should be the temperature of the sink keeping the temperature of the source constant?

Step-by-step solution

Efficiency of Carnot's engine, =25 %=0.25 Temperature of sink, T₂=27^ C =273+27=300 ~K Temperature of source =T₁ array ll & =1- T₂ T₁ & 0.25=1- T₂ T₁ & T₂ T₁ =1-0.25=0.75 & T₁= T₂ 0.75 = 300 0.75 =400 ~K & T₁=400 ~K array When efficiency, ^ =40 %=0.4 array ll then, & 1- T₂^ T₁ =0.4 T₂^ T₁ =1-0.4=0.6 & T₂^ =0.6 T₁=0.6 400=240 ~K array