Adiabatic Index Cp Cv — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Adiabatic Index (γ = Cp/Cv) Thermodynamics, particularly for ideal gases and adiabatic processes involving expansions or compressions (e.g., sound waves, internal combustion engines). Define Enthalpy H = U + PV. Differentiate with respect to Temperature to find Cp = dH/dT and Cv = dU/dT. For Ideal Gas, Cp - Cv = R (Mayer's Relation). Define ratio γ = Cp/Cv. C p > C v must hold true for stable substances (meaning γ > 1). Strictly constant only for Ideal Gases; varies with temperature for real gases. Assuming γ is always 1.4 (this is only true for diatomic ideal gases like air at standard conditions). Assuming γ has units (it is a dimensionless ratio). Confusing Cp and Cv, leading to a ratio < 1 (which violates thermodynamic stability).