# Commonly Used Physical Constants

Uncertainty should be read as 1.234(56) = 1.234$\pm$ 0.056
Name Symbol Value Units Relative Uncertainty
Speed of light (in vacuum) $c$  $299\ 792\ 458$  $\mathrm {m} \ \mathrm {s} ^{-1}$  (exact)
Magnetic Constant $\mu _{0}$  $4\pi \times 10^{-7}\approx 12.566\ 370\ 6\times 10^{-7}$  $\mathrm {N} \ \mathrm {A} ^{-2}$  (exact)
Electric Constant $\varepsilon _{0}=1/\left(\mu _{0}c^{2}\right)$  $\approx 8.854\ 187\ 817\times 10^{-12}$  $\mathrm {F} \ \mathrm {m} ^{-1}$  (exact)
Newtonian Gravitaional Constant $G$  $6.674\ 2(10)\times 10^{-11}$  $\mathrm {m} ^{3}\ \mathrm {kg} ^{-1}\ \mathrm {s} ^{-2}$  $1.5\times 10^{-4}$
Plank's Constant $h$  $6.626\ 069\ 3(11)\times 10^{-34}$  $\mathrm {J} \ \mathrm {s}$  $1.7\times 10^{-7}$
Elementary charge $e$  $1.602\ 176\ 53(14)\times 10^{-19}$  $\mathrm {C}$  $8.5\times 10^{-8}$
Mass of the electron $m_{e}$  $9.109\ 382\ 6(16)\times 10^{-31}$  $\mathrm {kg}$  $1.7\times 10^{-7}$
Mass of the proton $m_{p}$  $1.672\ 621\ 71(29)\times 10^{-27}$  $\mathrm {kg}$  $1.7\times 10^{-7}$
Fine structure constant $\alpha ={\frac {e^{2}}{4\pi \varepsilon _{0}\hbar c}}$  $7.297\ 352\ 568(24)\times 10^{-3}$  dimensionless $3.3\times 10^{-9}$
Molar gass constant $R$  $8.314\ 472(15)$  $\mathrm {J} \ \mathrm {mol} ^{-1}\ \mathrm {K} ^{-1}$  $1.7\times 10^{-6}$
Boltzmann's constant $k$  $1.380\ 650\ 5(24)\times 10^{-23}$  $\mathrm {J} \ \mathrm {K} ^{-1}$  $1.8\times 10^{-6}$
Avogadro's Number $N_{\text{A}},L$  $6.022\ 141\ 5(10)\times 10^{23}$  $\mathrm {mol} ^{-1}$  $1.7\times 10^{-7}$
Rydberg constant $R_{\infty }$  $10\ 973\ 731.568\ 525(73)$  $\mathrm {m} ^{-1}$  $6.6\times 10^{-12}$
Standard acceleration of gravity $g$  $9.806\ 65$  $\mathrm {m} \ \mathrm {s} ^{-2}$  defined
Atmospheric pressure $\mathrm {atm}$  $101\ 325$  $\mathrm {Pa}$  defined
Bohr Radius $a_{0}\$  $0.529\ 177\ 208\ 59(36)\times 10^{-10}\$  $\mathrm {m} \$  $6.8\times 10^{-10}$
Electron Volt $eV$  $1.602\ 176\ 53(14)\times 10^{-19}$  $\mathrm {J}$  $8.7\times 10^{-8}$
Luminous efficacy of monochromatic radiation $K_{cd}$  $683$  $\mathrm {lm/W}$  (exact)
hyperfine transition frequency of Cs-133 $\Delta \nu _{\text{Cs}}$  $9\ 192\ 631\ 770$  $\mathrm {Hz}$  (exact)
Reduced Planck constant $\hbar =h/2\pi$  $1.054\ 571\ 817\times {10}^{-34}$  $\mathrm {J} \cdot \mathrm {s}$  (exact)
atomic mass of Carbon 12 $m({}^{12}{\text{C}})$  $1.992\ 646\ 879\ 92(60)\times {10}^{-26}$  $\mathrm {kg}$
molar mass of Carbon-12 $M({}^{12}{\text{C}})=N_{\text{A}}m({}^{12}{\text{C}})$  $11.999\ 999\ 9958(36)\times {10}^{-3}$  $\mathrm {kg\cdot {mol}^{-1}}$
atomic mass constant $m_{\text{u}}=m({}^{12}{\text{C}})/12=1\,{\text{Da}}$  $1.660\ 539\ 066\ 60(50)\times {10}^{-27}$  $\mathrm {kg}$
molar mass constant $M_{\text{u}}=M({}^{12}{\text{C}})/12=N_{\text{A}}m_{\text{u}}$  $0.999\ 999\ 999\ 65(30)\times {10}^{-3}$  $\mathrm {kg\cdot {mol}^{-1}}$
molar volume of silicon $V_{m}(\mathrm {Si} )$  $1.205\ 883\ 199(60)\times {10}^{-5}$  $\mathrm {m^{3}\cdot {mol}^{-1}}$
molar Planck constant $N_{\text{A}}h$  $3.990\ 312\ 712\ldots {10}^{-10}$  $\mathrm {J\cdot {Hz}^{-1}\cdot {mol}^{-1}}$
Stefan-Boltzmann constant $\sigma =\pi ^{2}k_{B}^{4}/60\hbar ^{3}c^{2}$  $5.670\ 374\ 419\ldots \times {10}^{-8}$  $\mathrm {W\cdot m^{-2}\cdot K^{-4}}$
first radiation constant $c_{1}=2\pi hc^{2}$  $3.741\ 771\ 852\ldots {10}^{-16}$  $\mathrm {W\cdot m^{2}}$
first radiation constant for spectral radiance $c_{\text{1L}}=2hc^{2}/sr$  $1.191\ 042\ 972\ 397\ 188\ 414\ 079\ 4892\times {10}^{-16}$  $\mathrm {W\cdot m^{2}{sr}^{-1}}$
second radiation constant $c_{2}=hc/k_{B}$  $1.438\ 776\ 877\ldots \times {10}^{-2}$  $\mathrm {m\cdot K}$
Wien wavelength displacement constant $b$  $2.897\ 771\ 955\ldots \times {10}^{-3}$  $\mathrm {m\cdot K}$
Wien frequency displacement constant $b'=c/b$  $5.878\ 925\ 757\ \times {10}^{10}$  $\mathrm {Hz\cdot K^{-1}}$
Wien entropy displacement constant $b_{\text{entropy}}$  $3.002\ 916\ 077\ldots \times {10}^{-3}$  $\mathrm {m\cdot K}$
Faraday constant $F=N_{\text{A}}e$  $96\ 485.332\ 123\ 310\ 0184$  $\mathrm {C\cdot {mol}^{-1}}$

## To Be Merged Into Table

This list is prepared in the format

• Constant (symbol) : value

• Coulomb's Law Constant (k) : 1/(4 π ε0) = 9.0 × 109 N·m2/C2
• Faraday constant (F)  : 96,485 C·mol−1
• Mass of a neutron (mn) : 1.67495 × 10−27 kg
• Mass of Earth : 5.98 × 1024 kg
• Mass of the Moon : 7.35 × 1022 kg
• Mean radius of Earth : 6.37 × 106 m
• Mean radius of the Moon : 1.74 × 106 m
• Dirac's Constant ($\hbar$ ) : $h/(2\pi )$  = 1.05457148 × 10−34 J·s
• Speed of sound in air at STP : 3.31 × 102 m/s
• Unified Atomic Mass Unit (u) : 1.66 × 10−27 kg
 Item Proton Neutron Electron Mass 1 1 Negligible Charge +1 0 -1