Quantity
Symbol
Value
Relative Standard Uncertainty
characteristic impedance of vacuum
Z
0
=
μ
0
c
{\displaystyle Z_{0}=\mu _{0}c\,}
376.730 313 461... Ω
defined
electric constant (permittivity of free space)
ε
0
=
1
/
(
μ
0
c
2
)
{\displaystyle \varepsilon _{0}=1/(\mu _{0}c^{2})\,}
8.854 187 817... × 10-12 F·m-1
defined
magnetic constant (permeability of free space )
μ
0
{\displaystyle \mu _{0}\,}
4π × 10-7 N·A-2 = 1.2566 370 614... × 10-6 N·A-2
defined
gravitational constant (Newtonian constant of gravitation)
G
{\displaystyle G\,}
6.6742(10) × 10-11 m3 ·kg-1 ·s-2
1.5 × 10-4
Planck's constant
h
{\displaystyle h\,}
6.626 0693(11) × 10-34 J·s
1.7 × 10-7
Dirac's constant
ℏ
=
h
/
(
2
π
)
{\displaystyle \hbar =h/(2\pi )}
1.054 571 68(18) × 10-34 J·s
1.7 × 10-7
speed of light in vacuum
c
{\displaystyle c\,}
299 792 458 m·s-1
defined
Quantity
Symbol
Value1 (SI units)
Relative Standard Uncertainty
Bohr magneton
μ
B
=
e
ℏ
/
2
m
e
{\displaystyle \mu _{B}=e\hbar /2m_{e}}
927.400 949(80) × 10-26 J·T-1
8.6 × 10-8
conductance quantum
G
0
=
2
e
2
/
h
{\displaystyle G_{0}=2e^{2}/h\,}
7.748 091 733(26) × 10-5 S
3.3 × 10-9
Coulomb's constant
κ
=
1
/
4
π
ε
0
{\displaystyle \kappa =1/4\pi \varepsilon _{0}\,}
8.987 742 438 × 109 N·m2 C-2
defined
elementary charge
e
{\displaystyle e\,}
1.602 176 53(14) × 10-19 C
8.5 × 10-8
Josephson constant
K
J
=
2
e
/
h
{\displaystyle K_{J}=2e/h\,}
483 597.879(41) × 109 Hz· V-1
8.5 × 10-8
magnetic flux quantum
ϕ
0
=
h
/
2
e
{\displaystyle \phi _{0}=h/2e\,}
2.067 833 72(18) × 10-15 Wb
8.5 × 10-8
nuclear magneton
μ
N
=
e
ℏ
/
2
m
p
{\displaystyle \mu _{N}=e\hbar /2m_{p}}
5.050 783 43(43) × 10-27 J·T-1
8.6 × 10-8
resistance quantum
R
0
=
h
/
2
e
2
{\displaystyle R_{0}=h/2e^{2}\,}
12 906.403 725(43) Ω
3.3 × 10-9
von Klitzing constant
R
K
=
h
/
e
2
{\displaystyle R_{K}=h/e^{2}\,}
25 812.807 449(86) Ω
3.3 × 10-9
Quantity Symbol Value1 (SI units) Relative Standard Uncertainty
Bohr radius
a
0
=
α
/
4
π
R
∞
{\displaystyle a_{0}=\alpha /4\pi R_{\infty }\,}
0.529 177 2108(18) × 10-10 m
3.3 × 10-9
Fermi coupling constant
G
F
/
(
ℏ
c
)
3
{\displaystyle G_{F}/(\hbar c)^{3}}
1.166 39(1) × 10-5 GeV-2
8.6 × 10-6
fine structure constant
α
=
μ
0
e
2
c
/
(
2
h
)
=
e
2
/
(
4
π
ε
0
ℏ
c
)
{\displaystyle \alpha =\mu _{0}e^{2}c/(2h)=e^{2}/(4\pi \varepsilon _{0}\hbar c)\,}
7.297 352 568(24) × 10-3
3.3 × 10-9
Hartree energy
E
h
=
2
R
∞
h
c
{\displaystyle E_{h}=2R_{\infty }hc\,}
4.359 744 17(75) × 10-18 J
1.7 × 10-7
quantum of circulation
h
/
2
m
e
{\displaystyle h/2m_{e}\,}
3.636 947 550(24) × 10-4 m2 s-1
6.7 × 10-9
Rydberg constant
R
∞
=
α
2
m
e
c
/
2
h
{\displaystyle R_{\infty }=\alpha ^{2}m_{e}c/2h\,}
10 973 731.568 525(73) m-1
6.6 × 10-12
Thomson cross section
(
8
π
/
3
)
r
e
2
{\displaystyle (8\pi /3)r_{e}^{2}}
0.665 245 873(13) × 10-28 m2
2.0 × 10-8
Weinberg angle|weak mixing angle
sin
2
θ
W
=
1
−
(
m
W
/
m
Z
)
2
{\displaystyle \sin ^{2}\theta _{W}=1-(m_{W}/m_{Z})^{2}\,}
0.222 15(76)
3.4 × 10-3
Quantity Symbol Value1 (SI units) Relative Standard Uncertainty
atomic mass constant (unified atomic mass unit)
m
u
=
1
u
{\displaystyle m_{u}=1\ u\,}
1.660 538 86(28) × 10-27 kg
1.7 × 10-7
Avogadro's number
N
A
,
L
{\displaystyle N_{A},L\,}
6.0221417(10) × 1023
1.7 × 10-7
Boltzmann constant
k
=
R
/
N
A
{\displaystyle k=R/N_{A}\,}
1.380 6505(24) × 10-23 J·K-1
1.8 × 10-6
Faraday constant
F
=
N
A
e
{\displaystyle F=N_{A}e\,}
96 485.3383(83)C·mol-1
8.6 × 10-8
first radiation constant
c
1
=
2
π
h
c
2
{\displaystyle c_{1}=2\pi hc^{2}\,}
3.741 771 38(64) × 10-16 W·m2
1.7 × 10-7
for spectral radiance
c
1
L
{\displaystyle c_{1L}\,}
1.191 042 82(20) × 10-16 W · m2 sr-1
1.7 × 10-7
Loschmidt constant
at
T
{\displaystyle T}
p
{\displaystyle p}
n
0
=
N
A
/
V
m
{\displaystyle n_{0}=N_{A}/V_{m}\,}
2.686 7773(47) × 1025 m-3
1.8 × 10-6
gas constant
R
{\displaystyle R\,}
8.314 472(15) J·K-1 ·mol-1
1.7 × 10-6
molar Planck constant
N
A
h
{\displaystyle N_{A}h\,}
3.990 312 716(27) × 10-10 J · s · mol-1
6.7 × 10-9
molar volume of an ideal gas
at
T
{\displaystyle T}
p
{\displaystyle p}
V
m
=
R
T
/
p
{\displaystyle V_{m}=RT/p\,}
22.710 981(40) × 10-3 m3 ·mol-1
1.7 × 10-6
at
T
{\displaystyle T}
p
{\displaystyle p}
22.413 996(39) × 10-3 m3 ·mol-1
1.7 × 10-6
Sackur-Tetrode constant
at
T
{\displaystyle T}
p
{\displaystyle p}
S
0
/
R
=
5
2
{\displaystyle S_{0}/R={\frac {5}{2}}}
+
ln
[
(
2
π
m
u
k
T
/
h
2
)
3
/
2
k
T
/
p
]
{\displaystyle +\ln \left[(2\pi m_{u}kT/h^{2})^{3/2}kT/p\right]}
-1.151 7047(44)
3.8 × 10-6
at
T
{\displaystyle T}
p
{\displaystyle p}
-1.164 8677(44)
3.8 × 10-6
second radiation constant
c
2
=
h
c
/
k
{\displaystyle c_{2}=hc/k\,}
1.438 7752(25) × 10-2 m·K
1.7 × 10-6
Stefan-Boltzmann constant
σ
=
(
π
2
/
60
)
k
4
/
ℏ
3
c
2
{\displaystyle \sigma =(\pi ^{2}/60)k^{4}/\hbar ^{3}c^{2}}
5.670 400(40) × 10-8 W·m-2 ·K-4
7.0 × 10-6
Wien displacement law constant
b
=
(
h
c
/
k
)
/
{\displaystyle b=(hc/k)/\,}
2.897 7685(51) × 10-3 m · K
1.7 × 10-6
Quantity Symbol Value (SI units) Relative Standard Uncertainty
conventional value of Josephson constant2
K
J
−
90
{\displaystyle K_{J-90}\,}
483 597.9 × 109 Hz · V-1
defined
conventional value of von Klitzing constant3
R
K
−
90
{\displaystyle R_{K-90}\,}
25 812.807 Ω
defined
molar mass
constant
M
u
=
M
(
12
C
)
/
12
{\displaystyle M_{u}=M(\,^{12}{\mbox{C}})/12}
1 × 10-3 kg · mol-1
defined
of carbon-12
M
(
12
C
)
=
N
A
m
(
12
C
)
{\displaystyle M(\,^{12}{\mbox{C}})=N_{A}m(\,^{12}{\mbox{C}})}
12 × 10-3 kg · mol−1
defined
standard acceleration of gravity (free fall on Earth)
g
n
{\displaystyle g_{n}\,\!}
9.806 65 m·s-2
defined
standard atmosphere
atm
{\displaystyle {\mbox{atm}}\,}
101 325 Pa
defined
1 The values are given in the so-called concise form ; the number in brackets is the standard uncertainty , which is the value multiplied by the relative standard uncertainty .2 This is the value adopted internationally for realizing representations of the volt using the Josephson effect.3 This is the value adopted internationally for realizing representations of the ohm using the quantum Hall effect.
![{\displaystyle +\ln \left[(2\pi m_{u}kT/h^{2})^{3/2}kT/p\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/f620d502b24516f88ec1e1637e8a13ef534f127f)
