Physics Constants Reference
Common physics constants quick lookup, CODATA recommended values.
Universal constants
| Name | Symbol | Value | Unit | Instructions |
|---|---|---|---|---|
| speed of light | c | 2.998 × 10⁸ | m/s | speed of light in vacuum |
| Gravitational Constant | G | 6.674 × 10⁻¹¹ | N·m²/kg² | gravitational constant |
| Planck Constant | h | 6.626 × 10⁻³⁴ | J·s | fundamental constant in quantum mechanics |
| Reduced Planck Constant | ℏ | 1.055 × 10⁻³⁴ | J·s | ư = h/2π |
| Vacuum Permittivity | ε₀ | 8.854 × 10⁻¹² | F/m | vacuum permittivity |
| vacuum permeability | μ₀ | 4π × 10⁻⁷ | H/m | vacuum permeability |
| Avogadro Constant | Nₐ | 6.022 × 10²³ | mol⁻¹ | particles per mole |
| Boltzmann Constant | k | 1.381 × 10⁻²³ | J/K | Thermodynamic constant |
Atom / Particle
| Name | Symbol | Value | Unit | Instructions |
|---|---|---|---|---|
| elementary charge | e | 1.602 × 10⁻¹⁹ | C | electron/proton charge |
| electron mass | mₑ | 9.109 × 10⁻³¹ | kg | electron rest mass |
| proton mass | mₚ | 1.673 × 10⁻²⁷ | kg | proton rest mass |
| neutron mass | mₙ | 1.675 × 10⁻²⁷ | kg | neutron rest mass |
| Bohr radius | a₀ | 5.292 × 10⁻¹¹ | m | ground-state radius of hydrogen atom |
| Fine-Structure Constant | α | 7.297 × 10⁻³ | - | ≈ 1/137 |
Thermodynamics
| Name | Symbol | Value | Unit | Instructions |
|---|---|---|---|---|
| Gas Constant | R | 8.314 | J/(mol·K) | R = Nư · k |
| Stefan-Boltzmann Constant | σ | 5.670 × 10⁻⁸ | W/(m²·K⁴) | Blackbody Radiation |
| Wien Displacement Constant | b | 2.898 × 10⁻³ | m·K | Blackbody Radiation Peak |
| Standard atmosphere | atm | 1.013 × 10⁵ | Pa | Standard atmosphere |
| absolute zero | 0 K | -273.15 | ℃ | absolute zero |