Answer:
COP = 4.25
Step-by-step explanation:
It is given that,
Cooling temperature,
![T_c=-26^(\circ)C=273-26=247\ K](https://img.qammunity.org/2020/formulas/physics/college/40fco189ttzkz63t1z77014aylruljkm2k.png)
Heating temperature,
![T_h=50^(\circ)C=323\ K](https://img.qammunity.org/2020/formulas/physics/college/n2p1i6tcgwrkkxy4a3y5kgayf7klhkylbb.png)
We need to find the coefficient of performance. It is given by :
![COP=(T_h)/(T_h-T_c)](https://img.qammunity.org/2020/formulas/physics/college/oa6qk877byashq920sdl5cjmextjbg7ro5.png)
![COP=(323)/(323-247)](https://img.qammunity.org/2020/formulas/physics/college/yvps0oe4cndudiikrt0sg4vbuvtkk3sw5c.png)
COP = 4.25
So, the best coefficient of performance of a refrigerator is 4.45 Hence, this is the required solution.