Explain why you can’t cool down your kitchen by leaving your refrigerator or freezer door open with your refrigerator plugged in for an extended period of time.

Is a temperature difference necessary to operate a heat engine? State why or why not.

Consider two actual power plants operating with solar energy. Energy is supplied to one plant from a solar pond at 80°C and to the other from concentrating collectors that raise the water temperature to 600°C. Which of these power plants will have a higher efficiency? Explain.

A heat engine running backward is called a refrigerator if its purpose is to extract heat from a cold reservoir. The same engine running backward is called a heat pump if its purpose is to exhaust warm air into the hot reservoir. Heat pumps are widely used for home heating. You can think of a heat pump as a refrigerator that is cooling the already cold outdoors and, with its exhaust heat QH, warming the indoors. Perhaps this seems a little silly, but consider the following. Electricity can be directly used to heat a home by passing an electric current through a heating coil. This is a direct, 100% conversion of work to heat. That is, 19.0 kW of electric power (generated by doing work at the rate 19.0 kJ/s at the power plant) produces heat energy inside the home at a rate of 19.0 kJ/s. Suppose that the neighbor's home has a heat pump with a coefficient of performance of 3.00, a realistic value. NOTE: With a refrigerator, "what you get" is heat removed. But with a heat pump, "what you…

A window conducts power from a house to the cold outdoors. What power is conducted through a window of twice the area? Be specific 4x, 2x, the same, ½ x, ¼ x, etc. Explain your answer.

When the sun’s light hits the earth, the temperature rises. Is there an entropy change to accompany this transformation? Explain.

How can we apply the first law of thermodynamics to heat engines, heatpumps, and refrigerators?

In the shown Figure, the network done by the gas during the close cycle is equal to: P (P₂) 6x104 b 3x10² 0.4 a. 4.5kJ b. 20kJ c. 12kJ d. 8kJ e. 16kJ a 0.1 v (m³)

Why do refrigerators, air conditioners, and heat pumps operate most costeffectively for cycles with a small difference between Th and Tc? (Note that the temperatures of the cycle employed are crucial to its COP.)