# NEET Physics Thermodynamics Questions Solved

An ideal refrigerator has a freezer at a temperature of –13°C . The coefficient of performance of the engine is 5. The temperature of the air (to which heat is rejected) will be

(1) 325°C

(2) 325K

(3) 39°C

(4) 320°C

(3) Coefficient of performance

$K=\frac{{T}_{2}}{{T}_{1}-{T}_{2}}$$5=\frac{\left(273-13\right)}{{T}_{1}-\left(273-13\right)}=\frac{260}{{T}_{1}-260}$

$5{T}_{1}-1300=260$$5{T}_{1}=1560$

${T}_{1}=312K\to 39°C$

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