JEE Advanced
Physics
Thermodynamics
2025
JEE Advanced 2025 (Paper 2)
JEE Advanced Physics Question (2025) — Solution
Question
The efficiency of a Carnot engine operating with a hot reservoir kept at a temperature of 1000 K is 0.4. It extracts 150 J of heat per cycle from the hot reservoir. The work extracted from this engine is being fully used to run a heat pump which has a coefficient of performance 10 . The hot reservoir of the heat pump is at a temperature of 300 K . Which of the following statements is/are correct:
Options
- A. Work extracted from the Carnot engine in one cycle is 60 J .
- B. Temperature of the cold reservoir of the Carnot engine is 600 K .
- C. Temperature of the cold reservoir of the heat pump is 270 K .
- D. Heat supplied to the hot reservoir of the heat pump in one cycle is 540 J .
Answer
C. Temperature of the cold reservoir of the heat pump is 270 K .
Step-by-step solution
aligned & =0.4 \\ & ( COP )_ HP =10 \\ & ~W = Q _1=0.4 150=60 ~J \\ & COP = Dissered Effect Work input \\ & 10= Q _3 ~W \\ & Q _3=600 ~J \\ & Also \\ & =0.4=1- T _2 ~T _1 \\ & ~T _2=600 ~K \\ & COP = T _3 ~T _3- T _4 =10 aligned aligned & = 300 300- T _4 =10 \\ & ~T _4=270 ~K aligned
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