... conservation of energy and momentum.density of modes The number of modes of the radiation field in an energy range dE. Thedensity of modes is a function of the boundaryconditions ofthe spaceunder ... represents a degree of freedom of the distribution.(2) The number of independent coordinatesneeded for the description of the microscopicstate of a system is called the number of degrees of freedom. ... likely velocity of the distribution, T is theequilibriumtemperature oftheatoms, andm and M are their atomic and molar masses, respec-tively. k and R are the Boltzmann constant and general gas...