For an ideal gas the adiabatic equation linking pressure and volume is:

1. For an adiabatic (Q = 0) reversible process on an ideal gas, dU = −PdV. 2. Using dU = n Cv dT and the ideal gas law leads to PV^γ = constant. 3. The exponent γ = Cp/Cv > 1, so adiabats are STEEPER than isotherms (PV = const) on a P–V diagram. 4. Equivalent forms: T V^(γ−1) = const, T^γ P^(1−γ) = const. _Source: syllabus Physics Ch 11, §11.7 Adiabatic Process_