Suppose you want to operate an ideal refrigerator with a cold temperature of -10.0ºc , and you would like it to have a coefficient of performance of 7. 00. what is the hot reservoir temperature for such a refrigerator? (answer in ºc)

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.