Himanshu posted an Question
April 11, 2020 • 08:04 am 30 points
  • IIT JAM
  • Physics (PH)

Entropy for irreversible process

why for irreversible process calculating entropy is not possible??? we know it is greater than zero but how much we wouldn't able to calculate it. Moreover why entropy get decrease when Q heat is taken from system

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    Abhishek singh Best Answer

    Heat is associated with Thermal energy, which in turn is related to Kinetic energy of oscillation of particles. When you remove heat from a system, you are basically decreasing Kinetic energy of oscillating particles. Now what is entropy? it is the measure of randomness. what does it mean by randomness? it means rapidity of movement of particles. Now you can relate. when heat is taken out, particles will begin to move less rapidly. Thus the entropy decreases. Hope this will help. Best regards.

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    Dhairya sharma

    and irreversible processes are not state dependent.

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    Dhairya sharma

    because entropy is a state function it depends only on initial and final state. if we calculate entropy for initial to final or final to initial the chanz in entropy would be same. but if the process is irreversible then there isn't meaning of eNtropy .

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    ok and why it get decrease when Q heat is taken from system

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    and mam if entropy depends on intial and final point then are you want to say ki we don't now intial and final points in irreversible process

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    because dear, in irreversible process is that process there we can't get initial position under the same codn in which we were intial to final.

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    dQ= TdS if Q is extracted then Q will decrease hence s will decrease.

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