Show that an adiabatic curve is always stepped that . . .

Question : Show that an adiabatic curve is always stepped that an isothermal curve?


Doubt by Niyati

Solution : 

As we know, that adiabatic and isothermal curve are drawn between pressure (P) and volume (V) so their slope will be given by dP/dV.

In an isothermal process, 
PV = const.
differentiating both sides

In an adiabatic process, 
PVγ = cont.
differentiating both sides


From equation (1) and equation (2) 
Slope of Adiabatic curve = γ×Slope of Isothermal Curve

where γ is the ratio of two specific heats (Cp/Cv) which is always greater than 1. 

Hence, We have proved that adiabatic curve is always steeper than the isothermal curve.