Physical Constants
Reference
| symbol | name | value | unit | ||||
|---|---|---|---|---|---|---|---|
| c | speed of light in a vacuum |
299,792,458 | m/s | ||||
| G | gravitational constant |
6.67408 | × 10−11 | N m2/kg2 | |||
| h | planck constant |
6.62607015 4.13566770 |
× 10−34 × 10−15 |
J s eV s |
|||
| hc | h c |
1.98644586 1239.841984 |
× 10−25 |
J m eV nm |
|||
|
h bar reduced planck constant dirac constant |
1.05457182 6.58211957 |
× 10−34 × 10−16 |
J s eV s |
|||
| fCs |
hyperfine transition of 133Cs | 9,192,631,770 | Hz | ||||
| e | elementary charge |
1.602176634 | × 10−19 | C | |||
| ε0 | electric constant permitivitty of free space vacuum permitivitty |
8.854xxxxx | × 10−12 | C2/N m2 | |||
| μ0 | magnetic constant permeability of free space vacuum permeability |
4π | × 10−7 | T m/A | |||
| NA |
avogadro constant |
6.02214076 | × 1023 | 1/mol | |||
| k | boltzmann constant |
1.380649 | × 10−23 | J/K | |||
| R = NAk |
gas constant |
8.314462618 | J/mol K | ||||
|
stefan-boltzmann constant |
5.670370374419 | × 10−8 | W/m2K4 | |||
| b | wien displacement constant |
2.897771955 58.78xxxxx |
mm K GHz/K |
||||
| mu | atomic mass constant |
1.660xxxxx 931.4xxxxx 1 |
× 10−27 |
kg MeV u |
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| me | electron mass |
9.109xxxxx 0.5109xxxxx 0.0005485xxxxx |
× 10−31 |
kg MeV u |
|||
| mp | proton mass |
1.672xxxxx 938.2xxxxx 1.007xxxxx |
× 10−27 |
kg MeV u |
|||
| mn | neutron mass |
1.674xxxxx 939.5xxxxx 1.008xxxxx |
× 10−27 |
kg MeV u |
|||
| Kcd |
luminous efficacy |
683 | lm/W |
||||
| g | standard gravity |
9.80665 | m/s2 | ||||
| atm | standard atmosphere |
101,325 | Pa | ||||
| H0 | hubble constant* |
69.3 2.25 |
× 10−18 |
km/s/Mpc 1/s |
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