In order to solve this limitation of first law of thermodynamics, the second law of thermodynamics was discovered. In this example of coffee cup, first law of thermodynamics fails to determine the direction of spontaneous heat transfer (it does not say whether spontaneous heat transfer takes place from coffee to room or from room to coffee) This is only the limitation of first law of thermodynamics that it does not tell us the direction of the process to occurs. So this heat energy of the room can be transferred back to the coffee and coffee will become hot.īut in actual practice, we know that it is not possible and this heat will not enter the cup of coffee on it’s own.
First law of thermodynamics says that energy can be transferred from one form to another. Well, according to the first law of thermodynamics, this is possible. Is the reverse process possible? And will it occur on it’s own? In the left image you can see that the heat is released from the hot coffee cup and that is absolutely true. So I have prepared a simple example for you. I know, it’s difficult to understand this statement. “First law of thermodynamics: The net change in total energy of a system (∆E) is equal to the heat added to the system (Q) minus work done by the system (W).” In terms of heat, work and internal energy, the statement/definition of first law of thermodynamics can be stated as Now for the mathematical form, the equation of first law of thermodynamics includes heat (Q), work (W), and internal energy (U). “Energy can neither be created nor can be destroyed but transformation of one form into another form can be possible.” In previous section, we saw that 1st law of thermodynamics is nothing but a law of conservation of energy. Here I will explain you the entire concept hidden in the equation of 1st law of thermodynamics. Infact the example which I have mentioned in this explanation makes me remember the first law very easily. Now I have found the best way to remember this equation of first law of thermodynamics. When I was a student, I faced many problems in understanding the mathematical form of first law of thermodynamics.īut then I read from books, internet and I also learned from my teacher. Summary (Read this if you are in hurry).Why is absolute zero not possible? (simple).What is absolute zero temperature? Is it possible to achieve?.Entropy statement of Second law of thermodynamics.Second law of thermodynamics based on entropy.Second law of thermodynamics for heat pump/refrigerator (Clausius’s statement).
Example of the second law of thermodynamics how to#
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