Arefrigerator uses 40.0 j of work to extract heat from a heat reservoir at 0.00°c. if the coefficient of performance of the refrigerator is 2.10, then how much heat is discharged out of the refrigerator at a higher temperature?

Heat discharged out of the refrigerator  = 84 J

Explanation:

Coefficient of performance:

Ratio of work output to the amount of work or energy input. Coefficient of performance used generally as a measure of the energy ratio of air conditioners, space heaters. etc

Generally,  Coefficient of performance (COP) = Wok output/ work input

Work output = Heat discharged out of the refrigerator, Work input =  Electrical energy used by the refrigerator.

∴ Coefficient of performance (COP) = Heat discharged out of the refrigerator/ Electrical energy used by the refrigerator.

The energy used by the refrigerator = 40.0 J and

 Coefficient of performance (COP) =2.10.

Heat discharged out of the refrigerator = 40 × 2.10 = 84 J

∴ Heat discharged out of the refrigerator = 84 J

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask