In a P-V diagram (for an ideal gas), an isothermal curve will coincide within adiabatic curve (through a point), when___________________? August 30, 2021March 12, 2019 by admin In a P-V diagram (for an ideal gas), an isothermal curve will coincide within adiabatic curve (through a point), when___________________? A. Cp < CvB. Cp = Cv C. Cp > Cv D. C ≥ Cv