Introduction of Entropy

Introduction of Entropy
Lecture By: Er. Himanshu Vasishta, Tutorials Point India Private Limited

[TutorialsPoint_]

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[shkelqimfuga]

For causing an expansion in an ideal piston-cylinder system, we add heat to the system. As a consequence our system will produce a certain amount of work. This is work done by our system. To compress air in the cylinder a certain amount of work must me done on the system, therefore thermal energy will be released by the system (1st law of thermodynamics). What you were saying is that the temperature decreases in the system during expansion. Ofcourse I am talking about a non-adiabatic system. If we talk about an adiabatic system and we let the gas expand, this expansion must be compensated by a decrease in temperature (see adiabatic process with decrease in pressure).

How I understand entropy is: Entropy tells us something about the quality of energy. An increase in entropy is a decrease in the quality of the energy. Energy of the highest quality is work as it can (almost) totally be converted to heat. The reverse isn't the same as converting heat to work must be done with heat engines. If a system generates a big amount of entropy, it actually means that the thermal efficiency of the system is quite low and produces a lot of waste energy. If the generated entropy of the system equals to zero, we have an efficiency of an ideal heat engine (which is quite difficult to achieve because of the irreversibilities). In this case the expansion did useful work. The energy that is used to do this work cannot be used anymore, hence an increase in entropy. Correct me if I'm wrong. It's quite confusing without mentioning these important things. Thank you!

[saketg]

I think, when one says, "entropy is the amount of disorder in the system", I think one has to add, "on an atomic scale", otherwise it will be misleading because a glass of water looks more ordered than a bunch randomly shaped ice in the same glass, but we know the glass of water has higher entropy.

[Sharmasahil]

Sir your way of teaching is quite good. Keep it up. Your efforts help us to understand topic in depth👍

[m.s.arivalan]

Thanks for your video I understood sir
Can u brief introduction of enthalpy
How to tell heat and pressure combined as enthalpy?

[asifhusain]

Sir can you explain the basic concept of heat and temp how i differentiate them as i think temp is an unit that measures the hotness or coldness of a body and heat is form of energy that contains volume (nos of molecules) at specific temperature (ex 100°c) as we increase the volume(nos of molecules) at same temperature (100°c) is that mean we increase the heat Plz clear me anyone

[prayagpraveen]

You are Awesome sir... understanding the Concept Very very very nicely... Thank you so much ❤️❤️❤️❤️❤️❤️❤️❤️

[priyabratadash]

Temperature determines the direction of a thermodynamic process.

[yakooprajmuthalibu]

Index of unavailability degerataion of energy is called as entropy

[Entertainment-uize]

U confused me how temp is inversely proportional to entropy???

[madhusmitamoharana]

Rectification - entropy is directly propertional to temperature

[nituyadav]

Can you tell me please your property diagram process is feasible or not?

[balachbaloch]

way entropy increase less while temperature is higyh

[humairjahangir]

overall your lectures are good... but this comprehension has some flaws in it. being a lecturer of physics i can tell you what are those problems. if you will ask me then.

[zaeemshahzad]

While going from s2 to s1 entropy doesn't decrease. it always increase

[irfanullah-igwm]

How u say that sir
That if temp falls from T1 to T2 and
Volume will decrease.
If u change pressure
And temperature also less so if temp less how entopy becomes greater plz explain?

[bethasrikanth]

sir, maintain clear videos, without seeing how can we understand'