 # Thermodynamics: Stats

Physics
Terms

## Terms and Formulae

Terms Terms and Formulae

• ### Boltzmann Factor

Any term of the form e- /τ is called a Boltzmann Factor.

• ### Gibbs Factor

Any term of the form e(Nμ- )/τ is called a Gibbs factor.

• ### Gibbs Sum

The Gibbs Sum is the sum of all of the Gibbs Factors for the states and numbers of a system, and is given by:

ZG(μ, τ) =  e(Nμ- )/τ

• ### Partition Function

The Partition Function represents the sum of all of the Boltzmann Factors for the states of a system, and is given by:

Z = e- /τ

• ### Planck distribution function

The Planck distribution function describes the average number of photons < s > in a particular frequency σ for blackbody radiation and is given by:

< s > = • ### Stefan-Boltzmann law of radiation

The Stefan-Boltzmann law of radiation gives the energy density of radiation in a cavity, as can be expressed: = τ4

• ### Formulae

 The probability of finding a system in energy state if the system is in thermal contact with a reservoir P( ) = The entropy of blackbody radiation σ = ( )3