In a thermodynamic process, what indicates that a variable is not in equilibrium?
**Specific heat capacity** c = Q/(m ΔT) (J/kg·K), molar C = Q/(n ΔT), heat required to raise temperature, Q = m c ΔT, for water c=4186 J/kg·K, latent heat L = Q/m for phase change at constant temperature, fusion L_f and vaporization L_v, Q = m L, e.g., ice melting L_f=3.34×10⁵ J/kg, water vaporization 2.26×10⁶ J/kg. A system not in equilibrium has macroscopic variables (e.g., pressure, temperature) that change with time or vary across the system, such as during rapid expansion or explosive reactions, where uniformity is lost. Using first law ΔU = Q - W, W = ∫ P dV, isobaric W = P
Ref: NCERT > Physics Book > Thermodynamics > Specific Heat Capacity and Latent Heat