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Narayani Upadhyaya , asked a question
Subject: Chemistry , asked on 5/12/13

explain why cp is always greater than cv????

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Devilishly Cool , From Kendriya Vidyalaya No 2 , added an answer
Answered on 8/12/13

The reason for Cp greater than Cv is very simple.

This can be easily demonstrated by First law of thermodynamics.

At constant Pressure


Where as,

At Constant Volume,


Since dV=0

Therefore dQ=dU     ---(2).

Therefore Cp=dU+P.dV

And Cv=dU

Therefore using the above relation Cp is greater than Cv.

Physical Meaning of why Cp is greater than Cv:

At constant volume, heat is required only to increase the internal energy of system while At constant Pressure heat is needed for increasing Internal energy as well as for doing the work to displace the piston of system through a distance. Therefore Cp has a greater value than Cv.

Hope it helps!!


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Angel Malik , From Oxford Academy Rudrapur , added an answer
Answered on 8/3/12

thanx dude.. a thumbs up frm mah side.. :)

Kamalbista , added an answer
Answered on 5/12/12

explain why air temperature reading are always taken with thermometer in the shade?

Pavithra , From G K Shetty Vivekananda Vidyalaya , added an answer
Answered on 5/12/13

The air temperature reading is always taken in shade because due to the exposure of sunlight thermometer reading increases than the real temperature.

Pavithra , From G K Shetty Vivekananda Vidyalaya , added an answer
Answered on 5/12/13

I need a thumbs up.