Final answer:
Air conditioners and refrigerators transfer heat from a cooler environment to a warmer one. The coefficient of performance (COP) measures their efficiency.
Step-by-step explanation:
Air conditioners and refrigerators use the principles of thermodynamics to cool substances.
They achieve this by transferring energy in the form of heat from a cooler environment to a warmer one. The coefficient of performance (COP) is a measure of how efficiently an air conditioner or refrigerator operates. It is defined as the ratio of desired cooling (Qc) to the amount of work (W) required to achieve that cooling:
COP = Qc / W
The COP indicates how much cooling is achieved per unit of work input. A higher COP indicates a more efficient cooling process.