Govt Exams
When n = 0, PV⁰ = P = constant, which is an isobaric process. When n = 1 (isothermal), n = γ (adiabatic), n = ∞ (isochoric).
Compressibility factor Z = PV/(nRT). For ideal gas, Z = 1. For real gases, Z ≠ 1 due to molecular interactions.
Exergy is maximum work available from a system. At dead state (T₀, P₀, same as surroundings), exergy is zero as no useful work can be extracted.
Throttling is an isenthalpic process where enthalpy remains constant (H_initial = H_final) as the fluid expands through a restriction.
The Carnot efficiency is the maximum theoretical efficiency for any heat engine, given by η = 1 - (T_C/T_H), where temperatures are in Kelvin.
In an isochoric (constant volume) process, W = ∫PdV = 0 because volume does not change.
A reversible adiabatic process is also called isentropic, meaning entropy remains constant (ΔS = 0).
In an isothermal process, temperature is constant. For an ideal gas, internal energy depends only on temperature, so ΔU = 0.
The First Law of Thermodynamics states that energy cannot be created or destroyed, only converted from one form to another.
Temperature is an intensive property as it does not depend on the quantity of matter. Mass, volume, and weight are extensive properties.