Thermodynamics: notes and previous year questions

Free notes for every topic in thermodynamics, with the key formulas and real JEE and NEET questions solved step by step.

Zeroth Law of ThermodynamicsThermal equilibrium, the zeroth law, temperature versus heat, and the Celsius, Fahrenheit and Kelvin scales.
First Law of ThermodynamicsSystems and state variables, internal energy, heat and work, Q = ΔU + W with its signs, and the special processes.
Specific Heat and Molar Heat CapacityHeat capacity, specific and molar heat, Cᵥ and Cₚ, Mayer's relation, degrees of freedom, γ, mixtures and polytropic processes.
Thermodynamic ProcessesIsothermal, adiabatic, isobaric and isochoric processes: their laws, work, heat and curves.
PV Diagrams and Cyclic ProcessesReading states, work as a signed area, path dependence, cycles, and engines versus refrigerators.
Second Law of ThermodynamicsThe direction of natural processes: Kelvin–Planck and Clausius statements, efficiency and COP, reversibility and Carnot's theorem.
Heat Engines and Carnot CycleHow engines turn heat into work, the Carnot cycle and the best possible efficiency, real engine cycles and Carnot refrigerators.
Entropy and IrreversibilityEntropy as the number of ways, ΔS = Q/T, the entropy statement of the second law, ideal-gas entropy, irreversible processes and T–S diagrams.