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.
Although Boltzmann first linked entropy and probability in 1877, the relation was never expressed with a specific constant until Max Planck first introduced k, and gave a more precise value for it (1.346 × 10 −23 J/K, about 2.5% lower than today's figure), in his derivation of the law of black-body radiation in 1900–1901. [11]
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.
The Boltzmann equation or Boltzmann ... and the effect of gravitational collisions can be neglected for ... to study the cosmic microwave background radiation. ...
This equation and the usual ... is the Stefan–Boltzmann constant, c is the speed of light, k B is Boltzmann ... In the radiation zone gravity is balanced by the ...
At the same time, gravity will attempt to contract the system even further, and will do so on a free-fall time = / /, where is the universal gravitational constant, is the gas density within the region, and = / is the gas number density for mean mass per particle (μ = 3.9 × 10 −24 g is appropriate for molecular hydrogen with 20% helium by ...
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
where is the Boltzmann constant (also written as simply ) and equal to 1.380649 × 10 −23 J/K, and is the natural logarithm function (or log base e, as in the image above). In short, the Boltzmann formula shows the relationship between entropy and the number of ways the atoms or molecules of a certain kind of thermodynamic system can be arranged.