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

In summary, the conversation discusses the principles of the first and second laws of thermodynamics, specifically in relation to a closed system of a cylinder filled with ideal gas and a movable piston. The first law states that the change in heat energy (dQ) is equal to the change in internal energy (dU) plus the work done (dW). Meanwhile, the second law states that while mechanical energy can be fully converted into heat energy, the reverse is not possible. The question posed is how heat energy will be lost in a closed system with constant temperature, where dU is equal to 0 and dQ is equal to dU plus dW. It is mentioned that heat energy can be fully converted to work, but not through
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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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  • #2
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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FAQ: Question about the 2nd law of thermodynamics (heat loss)

What is the 2nd law of thermodynamics?

The 2nd law of thermodynamics states that the total entropy of an isolated system can never decrease over time. It can remain constant in ideal cases where the system is in a perfect state of equilibrium, but it usually increases. This law implies that energy transformations are not 100% efficient and some energy is always lost as heat.

How does the 2nd law of thermodynamics relate to heat loss?

The 2nd law of thermodynamics indicates that during any energy transfer or transformation, some energy will be lost as heat. This is because the process of energy conversion increases the system's entropy, and heat is a form of energy that is often dissipated into the surroundings, making it unavailable for doing work.

Can the 2nd law of thermodynamics be violated?

No, the 2nd law of thermodynamics cannot be violated. It is a fundamental principle of nature. Any process that appears to violate this law would imply a decrease in the total entropy of an isolated system, which is not possible according to our current understanding of physics.

What are some real-world examples of the 2nd law of thermodynamics in action?

Real-world examples include the operation of heat engines, refrigerators, and air conditioners. In each of these systems, energy is converted from one form to another, and some of it is invariably lost as heat. Another example is the natural process of heat flowing from a hot object to a cooler one until thermal equilibrium is reached.

How does the 2nd law of thermodynamics impact energy efficiency?

The 2nd law of thermodynamics sets a fundamental limit on the efficiency of energy conversion processes. Since some energy is always lost as heat, no process can be 100% efficient. This law drives the development of technologies aimed at minimizing energy loss and improving efficiency, such as better insulation materials and more efficient engines.

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