Search results
Results From The WOW.Com Content Network
The Stefan–Boltzmann law, also known as Stefan's law, describes the intensity of the thermal radiation emitted by matter in terms of that matter's temperature. It is named for Josef Stefan , who empirically derived the relationship, and Ludwig Boltzmann who derived the law theoretically.
Boltzmann constant: The Boltzmann constant, k, is one of seven fixed constants defining the International System of Units, the SI, with k = 1.380 649 x 10 −23 J K −1. The Boltzmann constant is a proportionality constant between the quantities temperature (with unit kelvin) and energy (with unit joule).
The collisionless Boltzmann equation, where individual collisions are replaced with long-range aggregated interactions, e.g. Coulomb interactions, is often called the Vlasov equation. This equation is more useful than the principal one above, yet still incomplete, since f cannot be solved unless the collision term in f is known.
The solution of the above integral yields a remarkably elegant equation for the total emissive power of a blackbody, the Stefan-Boltzmann law, which is given as, = where is the Steffan-Boltzmann constant.
Using simple algebra on equations , , and yields the result: = or =, where stands for the Boltzmann constant. Another equivalent result, using the fact that n R = N k B {\displaystyle nR=Nk_{\text{B}}} , where n is the number of moles in the gas and R is the universal gas constant , is: P V = n R T , {\displaystyle PV=nRT,} which is known as ...
From Boltzmann distribution we have for the number of excited atomic species i: = /, where n is the total number density of the atomic species, excited and unexcited, k is the Boltzmann constant, T is the temperature, is the degeneracy (also called the multiplicity) of state i, and Z is the partition function.
Radiation constant may refer to: The first and second radiation constants c 1 and c 2 – see Planck's Law The radiation density constant a – see Stefan–Boltzmann constant
[15] is a constant resulting from the maximization equation, k is the Boltzmann constant, h is the Planck constant, and T is the absolute temperature. With the emission now considered per unit frequency, this peak now corresponds to a wavelength about 76% longer than the peak considered per unit wavelength.