In this content - Thermal Physics, we basically discuss about Heat and Thermodynamics. In the part - Heat we start with the kinetic theory of gas by which we successfully discuss about the pressure equation of ideal gas and then we discuss Maxwell's velocity distribution among gas molecules. This gives average, root mean square velocity and most probable velocity of gas molecules. This also gives Boltzmann energy distribution from which we can establish the law of equipartition of energy. This velocity distribution can significantly be applied in transport phenomena and determination of mean free path of the gas molecules.

After that we discuss the thermodynamical aspect of matter through 1st, 2nd and 3rd law of thermodynamics. With the aspect of 1st law of thermodynamics, we discuss the features of molar specific heat of ideal and real gas and the difference between them. Also with the aspect of 1st law of thermodynamics, we discuss Universal Lapse Rate for temperature variation of atmosphere with altitude from sea level.

Before discussion of 2nd law of thermodynamics, we discuss about the efficiency of heat engine and coefficient of performance of refrigerator. After the statement of 2nd law of thermodynamics is discussed in this content along with the discussion of the efficiency of Carnot engine and Carnot theorem of reversible and irreversible heat engine. Several thermodynamic process like isothermal process, adiabatic process, reversible process, irreversible process along with other polytrophic process and their aspect regarding specific heat at the concerned process are discussed in details in this content.

After that Maxwell equation in thermodynamics involving several thermodynamic potentials are made discussed and it is then applied to Joule - Thomson Effect.