If a Carnot refrigerator is working between the 37° C and -3° C, then the COP of the refrigerator is:

CONCEPT:

Refrigerator:

• A refrigerator is a device that maintains a system or a body at a temperature lower than the surrounding temperature.
• In the refrigerator, the heat is removed from the low-temperature body and is rejected to the high-temperature body.
• Generally, the surrounding atmosphere acts as the high-temperature body for a refrigerator.

​Coefficient of Performance:

• The coefficient of performance is defined as the ratio of the desired output to the work input.
• The coefficient of performance of a refrigerator is given as,

\(⇒ COP_{R}=\frac{Q_{L}}{W}=\frac{Q_{L}}{Q_{H}-Q_{L}}=\frac{T_{L}}{T_{H}-T_{L}}\)

Where QL = heat removed from the system, QH = heat given to the surrounding, W = work input, TL = temperature of the system, and TH = temperature of the surrounding

CALCULATION:

Given T_L = -3° C = 270 K, and T₂ = 37° C = 310 K

• The coefficient of performance of a refrigerator is given as,

\(⇒ COP_{R}=\frac{T_{L}}{T_{H}-T_{L}}\)

\(⇒ COP_{R}=\frac{270}{310-270}\)

⇒ COP_R = 6.75

• Hence, option 1 is correct.