A refrigerator does 18 kJ of work while moving 115 kJ of thermal energy from inside the refrigerator. What is its coefficient of performance? (a) 3.4 (b) 2.8 (c) 8.9 (d) 6.4 (e) 5.2
The coefficient of performance (COP) of a refrigerator is defined as the ratio of the thermal energy moved from inside the refrigerator to the work done on the refrigerator. Mathematically, it is given by:
COP = (thermal energy moved from inside) / (work done on the refrigerator)
In this case, the thermal energy moved from inside the refrigerator is given as 115 kJ and the work done on the refrigerator is given as 18 kJ. Substituting these values into the equation for COP:
COP = 115 kJ / 18 kJ
COP ≈ 6.39
Rounded to the nearest tenth, the coefficient of performance is approximately 6.4.
Therefore, the correct option is (d) 6.4.
To find the coefficient of performance (COP) of a refrigerator, we can use the formula:
COP = Thermal Energy Moved / Work Input
Given:
Thermal Energy Moved = 115 kJ
Work Input = 18 kJ
Plugging these values into the formula, we get:
COP = 115 kJ / 18 kJ
COP = 6.4
Therefore, the coefficient of performance (COP) of the refrigerator is 6.4.
Therefore, the correct option is (d) 6.4.