Ratio of the universal gas constant (see gas laws) to Avogadro's number. It has a value of 1.380662 10^-23 joules per kelvin. Named after Ludwig Boltzmann, it is a fundamental constant of physics, occurring in nearly every statistical formulation of both classical and quantum physics
The physical constant relating energy at the particle level with temperature observed at the bulk level. It is the gas constant R divided by the Avogadro's number NA: - k = \frac{R}{N_{\rm A}}\