Second Law of Thermodynamics
Physics ⇒ Heat and Thermodynamics
Second Law of Thermodynamics starts at 11 and continues till grade 12.
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A Carnot engine operates between two heat reservoirs at temperatures 500 K and 300 K. What is the maximum possible efficiency of this engine?
A Carnot refrigerator operates between 250 K and 300 K. If it removes 500 J of heat from the cold reservoir, how much work does it require?
A heat engine absorbs 600 J of heat from a hot reservoir and does 150 J of work. How much heat is expelled to the cold reservoir?
A heat pump extracts 800 J of heat from the outside air at 270 K and delivers 1000 J of heat to a room at 300 K. How much work is required to operate the pump?
A refrigerator removes 2000 J of heat from its interior and expels 2500 J of heat to the surroundings. How much work does it require?
Define entropy in the context of thermodynamics.
Describe the difference between a reversible and an irreversible process in thermodynamics.
Explain in your own words what is meant by the 'irreversibility' of natural processes according to the Second Law of Thermodynamics.
Explain why perpetual motion machines of the second kind are impossible according to the Second Law of Thermodynamics.
Explain why the efficiency of real engines is always less than that of a Carnot engine operating between the same two temperatures.
If the entropy change of a system is -50 J/K and the entropy change of the surroundings is +70 J/K, what is the total entropy change of the universe?
State the Clausius statement of the Second Law of Thermodynamics.
A gas undergoes a reversible isothermal expansion at 350 K, absorbing 2100 J of heat from the surroundings. Calculate the change in entropy of the gas during this process.
A heat engine operates between three thermal reservoirs at temperatures 700 K, 400 K, and 200 K. If the engine absorbs 1200 J of heat from the 700 K reservoir, rejects 500 J to the 400 K reservoir, and the rest to the 200 K reservoir, calculate the total change in entropy of the universe for one complete cycle.
A student claims that it is possible to construct a heat engine that converts all the heat absorbed from a single reservoir into work, provided the process is carried out very slowly and reversibly. Critically analyze this claim using the Second Law of Thermodynamics.
Consider a system consisting of 2 moles of an ideal gas initially at 300 K. The gas is compressed isothermally and reversibly to half its initial volume. Calculate the change in entropy of the gas. (R = 8.314 J/mol·K)
Explain how the concept of entropy provides a microscopic interpretation of the Second Law of Thermodynamics.
