In a steam engine,steam at 140°C in a turbine does work on an external system,and the steam leaves the turbine at 100°C.The efficiency of the steam engine is 5%.The relevant physical principle is
A)the first law of thermodynamics.
B)the second law of thermodynamics.
C)specific heat capacity.
D)operation of a heat pump.
E)none of the above.

Question

Quizplus · Accepted Answer

The second law of thermodynamics states that no heat engine can be 100% efficient, meaning that some heat must always be lost in the process. In this case, the steam engine has an efficiency of only 5%, indicating that a significant amount of heat is being lost. The decrease in temperature from 140°C to 100°C also suggests that heat is being lost from the system. Therefore, the second law of thermodynamics is the relevant physical principle in this scenario.

In a Steam Engine,steam at 140°C in a Turbine Does