The ratio of the slopes of P-V graphs of adiabatic and isothermal process is(in terms of specific heat ratio γ)
γ
1+γ
1γ
1-γ
In isothermal process dPdVIsotherm=-PV---(1)
In adiabatic processdPdVAdiabatic=-γPV---(2)
From equation (2) divided by equation(1 )
⇒Ratio=slope of adiabatic processslope of isothermal process ⇒Ratio=-γPV-PV ⇒Ratio=γ