• question_answer A refrigerating machine in heat pump mode has a C.O.P. of 4. If it is worked in refrigerating mode with a power input of 3 kW, what is the heat extracted from the food kept in a refrigerator? A) 180 kJ/min                    B) 360 kJ/minC) 540 kJ/min                    D) 720 kJ/min

${{(COP)}_{HP}}=4$ ${{(COP)}_{\text{Ref}}}={{(COP)}_{HP}}-1=4-1=3$             $\frac{Q}{W}=\frac{Q}{3}$ $Q=9\,kW\,\,or\,\,540\,kJ/min$