Heat Engines and Refrigerators
Physics ⇒ Heat and Thermodynamics
Heat Engines and Refrigerators starts at 11 and continues till grade 12.
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A Carnot engine absorbs 1200 J of heat from the hot reservoir and rejects 900 J to the cold reservoir. What is its efficiency?
A Carnot engine operates between 400 K and 200 K. If it absorbs 600 J of heat from the hot reservoir, how much work does it perform?
A Carnot engine operates between a hot reservoir at 500 K and a cold reservoir at 300 K. What is the maximum possible efficiency of this engine?
A Carnot refrigerator operates between 250 K and 300 K. What is its maximum possible coefficient of performance (COP)?
A heat engine operates between 600 K and 300 K. What is the maximum efficiency it can achieve?
A heat engine receives 2000 J of heat from the hot reservoir and does 600 J of work. How much heat is expelled to the cold reservoir?
A heat pump delivers 3000 J of heat to a house for every 1000 J of work input. What is its coefficient of performance (COP)?
A refrigerator removes 500 J of heat from its interior and requires 125 J of work. What is its coefficient of performance (COP)?
Describe the main difference between a heat engine and a refrigerator.
Explain why a refrigerator cannot cool a room by leaving its door open.
Explain why no heat engine can be 100% efficient.
Explain why the efficiency of real engines is always less than that of a Carnot engine.
If a heat engine absorbs 1000 J of heat from the hot reservoir and rejects 600 J to the cold reservoir, how much work does it perform?
If the coefficient of performance (COP) of a refrigerator is 5 and it removes 1000 J of heat from the cold reservoir, how much work is required?
In a Carnot refrigerator, the work input is 200 J and the heat rejected to the hot reservoir is 800 J. How much heat is removed from the cold reservoir?
State the Clausius statement of the second law of thermodynamics.
State the Kelvin-Planck statement of the second law of thermodynamics.
A Carnot engine operates between two reservoirs at temperatures Th = 600 K and Tc = 300 K. If the engine produces 1500 J of work per cycle, how much heat is absorbed from the hot reservoir per cycle?
A certain heat engine operates between two reservoirs at temperatures Th and Tc. If the engine is modified so that the temperature of the hot reservoir is doubled while the cold reservoir temperature remains the same, by what factor does the maximum possible efficiency change?
A heat engine operates between a hot reservoir at 800 K and a cold reservoir at 400 K. If the engine absorbs 2000 J of heat from the hot reservoir, what is the minimum possible amount of heat that must be expelled to the cold reservoir?
