If Cp and Cv are the specific heats for a gas at constant pressure and at constant volume respectively, then the relation Cp-Cv=R is exact for? a) Ideal and real gases at all pressures b) Ideal gas at all pressures and real gas at a moderate pressure c) Ideal gas and nearly true for real gases at high pressure d) Ideal gas and nearly true for real gases at a moderate pressure

If Cp and Cv are the specific heats for a gas at constant pressure and at constant volume respectively, then the relation Cp-Cv=R is exact for? a) Ideal and real gases at all pressures b) Ideal gas at all pressures and real gas at a moderate pressure c) Ideal gas and nearly true for real gases at high pressure d) Ideal gas and nearly true for real gases at a moderate pressure