KCET2017PhysicsElectrostatics
For which combination of working temperatures, the efficiency of 'Carnot's engine' is the least ( ? )
Options
- A( 60 ~K , 40 ~K )
- B( 40 ~K , 20 ~K )
- C( 80 ~K , 60 ~K )
- D( 100 ~K , 80 ~K )
Correct answer
D. ( 100 ~K , 80 ~K )
Step-by-step solution
Efficiency of Carnot's engine is given as ( =1- T₂ T₁ ) For ( T₁=60 ~K ) and ( T₂=40 ~K , =1- 40 60 =0.333 ) For ( T₁=40 ~K ) and ( T₂=20 ~K , =1- 20 40 =0.5 ) For ( T₁=80 K ) and ( T₂=60 K, =1- 60 80 =0.25 ) For ( T₁=100 ~K ) and ( T₂=80 ~K , =1- 80 100 =0.2 ) Therefore, the efficiency of Carnot's engine is the least for ( T₁=100 ~K ) and ( T₂=80 ~K )