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The Debye model is a solid-state equivalent of Planck's law of black body radiation, which treats electromagnetic radiation as a photon gas confined in a vacuum space. Correspondingly, the Debye model treats atomic vibrations as phonons confined in the solid's volume. Most of the calculation steps are identical, as both are examples of a ...
A temperature coefficient describes the relative change of a physical property that is associated with a given change in temperature. For a property R that changes when the temperature changes by dT, the temperature coefficient α is defined by the following equation: Here α has the dimension of an inverse temperature and can be expressed e.g ...
A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location.
Common thermodynamic equations and quantities in thermodynamics, using mathematical notation, are as follows:
In physics, the Saha ionization equation is an expression that relates the ionization state of a gas in thermal equilibrium to the temperature and pressure. [1] [2] The equation is a result of combining ideas of quantum mechanics and statistical mechanics and is used to explain the spectral classification of stars.
Thermodynamic temperature, as distinct from SI temperature, is defined in terms of a macroscopic Carnot cycle. Thermodynamic temperature is of importance in thermodynamics because it is defined in purely thermodynamic terms. SI temperature is conceptually far different from thermodynamic temperature. Thermodynamic temperature was rigorously ...
Heat equation Animated plot of the evolution of the temperature in a square metal plate as predicted by the heat equation. The height and redness indicate the temperature at each point. The initial state has a uniformly hot hoof-shaped region (red) surrounded by uniformly cold region (yellow). As time passes the heat diffuses into the cold region.
The Gibbs–Helmholtz equation is a thermodynamic equation used to calculate changes in the Gibbs free energy of a system as a function of temperature. It was originally presented in an 1882 paper entitled " Die Thermodynamik chemischer Vorgänge " by Hermann von Helmholtz. It describes how the Gibbs free energy, which was presented originally ...