Question about the 2nd law of thermodynamics (heat loss)

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SUMMARY

The discussion centers on the 2nd law of thermodynamics as it applies to a closed system with an ideal gas in a cylinder featuring a movable piston. It establishes that while mechanical energy can be fully converted into heat energy, the reverse is not true; heat energy cannot be completely transformed into mechanical energy. The question posed addresses the loss of heat energy when heat is added to the cylinder at constant temperature, emphasizing that while dU equals zero, heat energy can be converted to work, but not in a cyclic process.

PREREQUISITES
  • Understanding of the first law of thermodynamics (dQ = dU + dW)
  • Familiarity with the second law of thermodynamics and its implications
  • Knowledge of ideal gas behavior and properties
  • Concept of thermodynamic cycles and their limitations
NEXT STEPS
  • Study the implications of the Carnot cycle on heat engines
  • Explore the concept of entropy and its role in thermodynamic processes
  • Investigate real-world applications of the second law in engineering
  • Learn about the efficiency of heat engines and the factors affecting it
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Students of thermodynamics, mechanical engineers, physicists, and anyone interested in the principles governing energy conversion and heat transfer in closed systems.

Shovon00000
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Assume that a closed system of cylindar filled with ideal gas consists of a movable piston.We know from the 1st law dQ=dU +dW.
According to the 2nd law mechanical energy can be totally converted into heat energy but heat energy cannot be converted completely into mechanical energy.The question is"If we give heat to the cylindar and keep the temperature constant how will some of the heat energy be lost ?(here dU=0,and we know dQ=dU+dW)
 
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You can completely convert heat energy to work. You just can't do it by operating the system in a cycle.
 
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