A refrigerator that consumes 3 kW of electricity when running and has a coefficient of performance of 1.5 is placed in a well-sealed room, and is plugged in with its door open. The rate of cooling or heating this refrigerator will provide to the air in the room when running isQuestion 8Select one:a.3 kJ/s, coolingb.4.5 kJ/s, coolingc.2 kJ/s, heatingd.4.5 kJ/s, heatinge.3 kJ/s, heating
Question
A refrigerator that consumes 3 kW of electricity when running and has a coefficient of performance of 1.5 is placed in a well-sealed room, and is plugged in with its door open. The rate of cooling or heating this refrigerator will provide to the air in the room when running isQuestion 8Select one:a.3 kJ/s, coolingb.4.5 kJ/s, coolingc.2 kJ/s, heatingd.4.5 kJ/s, heatinge.3 kJ/s, heating
Solution
The coefficient of performance (COP) of a refrigerator is the ratio of the cooling it provides to the electrical energy it consumes. In this case, the refrigerator consumes 3 kW of electricity and has a COP of 1.5. This means that for every 1 kW of electricity it consumes, it provides 1.5 kW of cooling.
Therefore, the total cooling provided by the refrigerator is 3 kW * 1.5 = 4.5 kW.
However, since the refrigerator is in a well-sealed room with its door open, the heat it generates from running will also be added to the room. This heat is equal to the electrical energy it consumes, which is 3 kW.
So, the net effect on the room is the cooling provided by the refrigerator minus the heat it generates, which is 4.5 kW - 3 kW = 1.5 kW.
But since the refrigerator is adding heat to the room as well as removing it, the net effect is actually heating, not cooling.
Therefore, the correct answer is 1.5 kJ/s, heating. However, this option is not listed in the choices. The closest answer would be 2 kJ/s, heating (option c), but this is not exactly correct.
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