UPSEE Solved Model Paper 2

For isothermal expansion PV = constant. Partially differentiating we have
VΔP + PΔV = 0
or

ΔP

ΔV

= −

P

V

For adiabatic expansion PVγ = constant. Partially differentiatinf we have
VγΔP+γVγ−1ΔVP = 0
or

ΔP

ΔV

= −

γP

V

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