25.3: Constants of Nature

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\[\begin{equation}
\begin{array}{lcl}
\text { Symbol } & \text { Value } & \text { Meaning } \\
h & 6.63 \times 10^{-34} \mathrm{~J} \mathrm{~s} & \text { Planck's constant } \\
\hbar & 1.06 \times 10^{-34} \mathrm{~J} \mathrm{~s} & h(2 \pi) \\
c & 2.998 \times 10^{8} \mathrm{~m} \mathrm{~s}^{-1} & \text { speed of light } \\
G & 6.67 \times 10^{-11} \mathrm{~m}^{3} \mathrm{~s}^{-2} \mathrm{~kg}^{-1} & \text { universal gravitational constant } \\
k_{B} & 1.38 \times 10^{-23} \mathrm{~J} \mathrm{~K}^{-1} & \text { Boltzmann's constant } \\
\sigma & 5.67 \times 10^{-8} \mathrm{~W} \mathrm{~m}^{-2} \mathrm{~K}^{-4} & \text { Stefan-Boltzmann constant } \\
K & 3.67 \times 10^{11} \mathrm{~s}^{-1} \mathrm{~K}^{-1} & \text { thermal frequency constant } \\
\epsilon_{0} & 8.85 \times 10^{-12} \mathrm{C}^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2} & \text { permittivity of free space } \\
\mu_{0} & 4 \pi \times 10^{-7} \mathrm{~N} \mathrm{~s}^{2} \mathrm{C}^{-2} & \text { permeability of free space }\left(=1 /\left(\epsilon_{0} c^{2}\right)\right)
\end{array}
\end{equation} \nonumber\]