In Fig., Curves AB and CD represent The Relation Between Pressure P and Volume V of An Ideal Gas. One Of The Curves Represents An Isothermal Expansion And The Other Represents An Adiabatic Expansion. Which Curve Represents An Adiabatic Expansion?                                                                             

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In Fig., curves AB and CD represent the relation between pressure P and volume V of an ideal gas. One of the curves represents an isothermal expansion and the other represents an adiabatic expansion. Which curve represents an adiabatic expansion?



Correct option is

Curve CD


For isothermal expansion PV =  constant. Partially differentiating we have




Partially differentiating we have



Thus the slope at any point on the adiabatic curve is  times that for isothermal curve. Hence curve CD represents adiabatic expansion.




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