Physical Constants: neutron_mass to stefan_boltzmann
Physical constants — fundamental constants of nature (speed of light, gravitational constant, Boltzmann, Planck, etc.) with SI and imperial values
| constant name | category | description | symbol | uncertainty | unit SI | unit imperial | value SI | value imperial |
|---|---|---|---|---|---|---|---|---|
| neutron_mass | atomic | Neutron rest mass | m_n | 5.7e-10 | kg | kg | 0 | 0 |
| planck_constant | atomic | Planck constant | h | exact (defined) | J*s | J*s | 0 | 0 |
| solar_constant | thermodynamics | Total solar irradiance at mean Earth-Sun distance | G_sc | 0.003 | W/m^2 | BTU/(hr*ft^2) | 1,361 | 431.6 |
| speed_of_sound_air | fluid_properties | Speed of sound in dry air at 20 degC, 1 atm | a_air | 0.002 | m/s | ft/s | 343.21 | 1,126 |
| stefan_boltzmann | thermodynamics | Stefan-Boltzmann constant | sigma | exact (defined) | W/(m^2*K^4) | BTU/(hr*ft^2*R^4) | 0 | 0 |
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