Boltzmann Constant

$$\begin{array}{rl}{k}_B& =\frac{PV}{NT}\frac{\mathrm{J}}{\mathrm{K}}\\ & =1.380649\cdot 10^{-23}\frac{\mathrm{J}}{\mathrm{K}}\\ & =8.617333262\cdot 10^{-5}\frac{\mathrm{eV}}{\mathrm{K}}\end{array}$$

• Analogous to $R=\frac{PV}{nT}$, where $n$ is the number of moles of the ideal gas
• $P$ is the pressure of the container of the gas
• $V$ is the volume of the gas
• $N$ is the number of particles of the gas
• $T$ is the temperature of the gas
• The numerical constant is exact!