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Fundamental Constants
| Constant | Symbol | Value | ||
|---|---|---|---|---|
| Power of 10 | Units | |||
| Speed of light | c | 2.997 924 58 a | 108 | m s−1 |
| Elementary charge | e | 1.602 176 634 a | 10−19 | C |
| Planck’s constant | h | 6.626 070 15 a | 10−34 | J s |
| ħ = h/2π | 1.054 571 817 | 10−34 | J s | |
| Boltzmann’s constant | k | 1.380 649 a | 10−23 | J K−1 |
| Avogadro’s constant | NA | 6.022 140 76 a | 1023 | mol−1 |
| Gas constant | R = NAk | 8.314 462 618 | J K−1 mol−1 | |
| Faraday’s constant | F = NAe | 9.648 533 21 | 104 | C mol−1 |
| Mass | ||||
| Electron | me | 9.109 383 7015 | 10−31 | kg |
| Proton | mp | 1.672 621 923 69 | 10−27 | kg |
| Neutron | mn | 1.674 927 498 04 | 10−27 | kg |
| Atomic mass constant | mu | 1.660 539 066 60 | 10−27 | kg |
| Magnetic constant (vacuum permeability) | μ0 | 1.256 637 062 12 | 10−6 | J s2 C−2 m−1 |
| Electric constant (vacuum permittivity) | 8.854 187 8128 | 10−12 | J−1 C2 m−1 | |
| 4πɛ0 | 1.112 650 056 | 10−10 | J−1 C2 m−1 | |
| Bohr magneton | μB = eħ/2me | 9.274 010 0783 | 10−24 | J T−1 |
| Nuclear magneton | μN = eħ/2mp | 5.050 783 7461 | 10−27 | J T−1 |
| Proton magnetic moment | μp | 1.410 606 797 36 | 10−26 | J T−1 |
| g-Factor of electron | ge | 2.002 319 304 362 56 | ||
| Magnetogyric ratio | ||||
| Electron | γe = gee/2me | 1.760 859 630 23 | 1011 | T−1 s−1 |
| Proton | γp = 2μp/ħ | 2.675 221 8744 | 108 | T−1 s−1 |
| Bohr radius | a0 = 4πɛ0ħ 2/e 2me | 5.291 772 109 03 | 10−11 | m |
| Rydberg constant | R̃∞ = mee 4/8h 3cɛ0 2 | 1.097 373 1568 | 105 | cm−1 |
| hcR̃∞/e | 13.605 693 12 | eV | ||
| Fine-structure constant | α = μ0e 2c/2h | 7.297 352 5693 | 10−3 | |
| α −1 | 1.370 359 990 084 | 102 | ||
| Stefan–Boltzmann constant | σ = 2π5k 4/15h 3c 2 | 5.670 374 419 | 10−8 | W m−2 K−4 |
| Second radiation constant | c2 = hc/k | 1.438 776 877 | 10−2 | m K−1 |
| Standard acceleration of free fall | g | 9.806 65 a | m s−2 | |
| Gravitational constant | G | 6.674 30 | 10−11 | N m2 kg−2 |
| Constant | Symbol | Value | ||
|---|---|---|---|---|
| Power of 10 | Units | |||
| Speed of light | c | 2.997 924 58 a | 108 | m s−1 |
| Elementary charge | e | 1.602 176 634 a | 10−19 | C |
| Planck’s constant | h | 6.626 070 15 a | 10−34 | J s |
| ħ = h/2π | 1.054 571 817 | 10−34 | J s | |
| Boltzmann’s constant | k | 1.380 649 a | 10−23 | J K−1 |
| Avogadro’s constant | NA | 6.022 140 76 a | 1023 | mol−1 |
| Gas constant | R = NAk | 8.314 462 618 | J K−1 mol−1 | |
| Faraday’s constant | F = NAe | 9.648 533 21 | 104 | C mol−1 |
| Mass | ||||
| Electron | me | 9.109 383 7015 | 10−31 | kg |
| Proton | mp | 1.672 621 923 69 | 10−27 | kg |
| Neutron | mn | 1.674 927 498 04 | 10−27 | kg |
| Atomic mass constant | mu | 1.660 539 066 60 | 10−27 | kg |
| Magnetic constant (vacuum permeability) | μ0 | 1.256 637 062 12 | 10−6 | J s2 C−2 m−1 |
| Electric constant (vacuum permittivity) | 8.854 187 8128 | 10−12 | J−1 C2 m−1 | |
| 4πɛ0 | 1.112 650 056 | 10−10 | J−1 C2 m−1 | |
| Bohr magneton | μB = eħ/2me | 9.274 010 0783 | 10−24 | J T−1 |
| Nuclear magneton | μN = eħ/2mp | 5.050 783 7461 | 10−27 | J T−1 |
| Proton magnetic moment | μp | 1.410 606 797 36 | 10−26 | J T−1 |
| g-Factor of electron | ge | 2.002 319 304 362 56 | ||
| Magnetogyric ratio | ||||
| Electron | γe = gee/2me | 1.760 859 630 23 | 1011 | T−1 s−1 |
| Proton | γp = 2μp/ħ | 2.675 221 8744 | 108 | T−1 s−1 |
| Bohr radius | a0 = 4πɛ0ħ 2/e 2me | 5.291 772 109 03 | 10−11 | m |
| Rydberg constant | R̃∞ = mee 4/8h 3cɛ0 2 | 1.097 373 1568 | 105 | cm−1 |
| hcR̃∞/e | 13.605 693 12 | eV | ||
| Fine-structure constant | α = μ0e 2c/2h | 7.297 352 5693 | 10−3 | |
| α −1 | 1.370 359 990 084 | 102 | ||
| Stefan–Boltzmann constant | σ = 2π5k 4/15h 3c 2 | 5.670 374 419 | 10−8 | W m−2 K−4 |
| Second radiation constant | c2 = hc/k | 1.438 776 877 | 10−2 | m K−1 |
| Standard acceleration of free fall | g | 9.806 65 a | m s−2 | |
| Gravitational constant | G | 6.674 30 | 10−11 | N m2 kg−2 |
a
Exact, defined value.
Greek Alphabet a
| A, α | alpha | I, ι | iota | P, ρ | rho |
| B, β | beta | K, κ | kappa | Σ, σ | sigma |
| Γ, γ | gamma | Λ, λ | lambda | T, τ | tau |
| Δ, δ | delta | M, μ | mu | Y, υ | upsilon |
| E, ɛ | epsilon | N, ν | nu | Φ, ϕ | phi |
| Z, ζ | zeta | Ξ, ξ | xi | X, χ | chi |
| H, η | eta | O, ο | omicron | Ψ, ψ | psi |
| Θ, θ | theta | Π, π | pi | Ω, ω | omega |
| A, α | alpha | I, ι | iota | P, ρ | rho |
| B, β | beta | K, κ | kappa | Σ, σ | sigma |
| Γ, γ | gamma | Λ, λ | lambda | T, τ | tau |
| Δ, δ | delta | M, μ | mu | Y, υ | upsilon |
| E, ɛ | epsilon | N, ν | nu | Φ, ϕ | phi |
| Z, ζ | zeta | Ξ, ξ | xi | X, χ | chi |
| H, η | eta | O, ο | omicron | Ψ, ψ | psi |
| Θ, θ | theta | Π, π | pi | Ω, ω | omega |
a
Oblique versions (α, β, …) are used to denote physical observables.
SI Prefixes
| y | z | a | f | p | n | μ | m | c | d |
| yocto | zepto | atto | femto | pico | nano | micro | milli | centi | deci |
| 10−24 | 10−21 | 10−18 | 10−15 | 10−12 | 10−9 | 10−6 | 10−3 | 10−2 | 10−1 |
| y | z | a | f | p | n | μ | m | c | d |
| yocto | zepto | atto | femto | pico | nano | micro | milli | centi | deci |
| 10−24 | 10−21 | 10−18 | 10−15 | 10−12 | 10−9 | 10−6 | 10−3 | 10−2 | 10−1 |
| Da | h | k | M | G | T | P | E | Z | Y |
| deca | hecto | kilo | mega | giga | tera | peta | exa | zetta | yotta |
| 10 | 102 | 103 | 106 | 109 | 1012 | 1015 | 1018 | 1021 | 1024 |
| Da | h | k | M | G | T | P | E | Z | Y |
| deca | hecto | kilo | mega | giga | tera | peta | exa | zetta | yotta |
| 10 | 102 | 103 | 106 | 109 | 1012 | 1015 | 1018 | 1021 | 1024 |
