Physics Thermodynamics Syllabus for NEET 2026

Thermodynamics explains how heat, work, and energy are related during physical and chemical processes. It studies the transfer of thermal energy between systems and surroundings and describes how energy changes from one form to another under different conditions.

This unit introduces important thermodynamic laws, thermal equilibrium, internal energy, and energy conservation principles. It also explains processes such as isothermal and adiabatic changes along with reversible and irreversible processes that govern the behavior of gases and thermal systems.

Thermal Equilibrium and Zeroth Law of Thermodynamics

Thermal equilibrium occurs when two bodies in contact do not exchange heat energy. The Zeroth Law of Thermodynamics forms the basis of temperature measurement.

It states that if two systems are separately in thermal equilibrium with a third system, they are also in equilibrium with each other.

Temperature helps determine the direction of heat flow between systems.

Heat, Work, and Internal Energy

Heat is the energy transferred due to temperature difference, while work is the energy transfer caused by mechanical action.

Internal energy is the total kinetic and potential energy of molecules inside a system.

The First Law of Thermodynamics represents conservation of energy and relates heat, work, and internal energy.

Thermodynamic Processes

An isothermal process occurs at constant temperature, where heat exchange takes place with the surroundings.

An adiabatic process occurs without heat exchange between the system and the surroundings.

These processes are important for understanding energy transfer and the behaviour of gases under changing conditions.

Second Law of Thermodynamics

The Second Law of Thermodynamics explains the natural direction of heat flow and limitations in energy conversion.

Heat naturally flows from a higher temperature to a lower temperature. No engine can convert all heat completely into work.

Processes may be:

• Reversible → Ideal and perfectly efficient

• Irreversible → Real processes involving energy loss

Thermodynamics: Complete Study Resources By PW

To improve preparation and revision, PW provides conceptual questions, formulas, and thermodynamic process-based numericals to help you practice regularly.