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← JEE Main 2016 · 10 Apr · Shift 1
PhysicsSingle correct+4 / -1Question 8 of 90

JEE Main 2016 · 10 Apr · Shift 1, Physics question 8

A Carnot freezer takes heat from water at 0°C inside it and rejects it to the room at a temperature of 27°C. The latent heat of ice is 336×103336\times10^3 J kg−1^{-1}. If 5 kg of water at 0°C is converted into ice at 0°C by the freezer, then the energy consumed by the freezer is close to :

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Answer and worked solution

Official answer: A

Heat removed: Qc=5×336×103=1.68×106Q_c=5\times336\times10^3=1.68\times10^6 J. For a Carnot freezer,
W=QcTh−TcTc=1.68×106×27273≈1.67×105 J.W=Q_c\frac{T_h-T_c}{T_c}=1.68\times10^6\times\frac{27}{273}\approx1.67\times10^5\text{ J}.