If the coefficient of performance of a refrigerator is 5 and it operates at room temperature (27°C), find the temperature inside the refrigerator.

Hint: The refrigerator delivers the heat to the room at a higher temperature.
Step 1: Use the formula of coefficient of performance of the refrigerator.
Given, the coefficient of performance,
(β)=5
T1=(27+273)K=300K,T2=?
Coefficient of performance, (β)=T2T1-T2
    5=T2300-T21500-5T2=T2
6T2=1500T2=250K
T2=(250-273)°C=-23°C