Some useful constants are given here.
| Quantity | Symbol | Value | SI units |
|---|---|---|---|
| Velocity of light | c | 2.997925 x 108 | m s-1 |
| Elementary charge | e | 1.60219 x 10-19 | C |
| Planck’s constant | h | 6.62620 x 10-34 | J s |
| Reduced Planck’s constant | ħ = h/2π | 1.05459 x 10-34 | J s |
| Avogadro’s number | NA | 6.02217 x 1023 | mol-1 |
| Atomic mass unit | amu | 1.66053 x 10-27 | kg |
| Electron rest mass | me | 9.10956 x 10-31 | kg |
| Proton rest mass | mp | 1.67261 x 10-27 | kg |
| Bohr radius ħ2/me2 | r0 | 5.29177 x 10-11 | m |
| Rydberg constant me4/2ħ2 | Ry | 2.17991 x 10-18 | J |
| electron volt | eV | 1.60219 x 10-19 | J |
| Boltzmann constant | kB | 1.38062 x 10-23 | J K-1 |
| Permittivity of free space | ε0 | 107/4πc2 | |
| Permeability of free space | μ0 | 4π | 107 |
References: Charles Kittel, Introduction to Solid State Physics, 7th Ed.
Materials Scientist 