On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (∂P/∂V)S and the slope of the reversible isothermal line (∂P/∂V)T are related as (where, y = Cp/Cv) )

• A. (∂P/∂V)S = (∂P/∂V)T
• B. (∂P/∂V)S = 1/y(∂P/∂V)T
• C. (∂P/∂V)S = [(∂P/∂V)T]Y
• D. (∂P/∂V)S = y(∂P/∂V)T

Answer: (D)