Physical constants¶
Contains useful physical constants. Fundamental constants can be also found in sympy.physics.units module.
- standard_conditions_temperature¶
Zero Celsius degrees. The
temperatureat which water freezes. It is also temperature for Standard Temperature and Pressure (STP)Links:
- Symbol:
t_std- Latex:
\(t_\text{std}\)
- Dimension:
temperature
- standard_laboratory_temperature¶
Approximately \(25\) degrees Celsius. Commonly used
temperaturefor tabulation purposes.Links:
- Symbol:
t_lab- Latex:
\(t_\text{lab}\)
- Dimension:
temperature
- electron_rest_mass¶
massof stationary electron.Links:
- Symbol:
m_e- Latex:
\(m_\text{e}\)
- Dimension:
mass
- bohr_radius¶
The Bohr radius is the radius of the electron orbit of the hydrogen atom closest to the nucleus in the atomic model proposed by Niels Bohr.
Links:
- Symbol:
a0- Latex:
\(a_0\)
- Dimension:
length
- hydrogen_ionization_energy¶
The ionization energy is the smallest energy required to remove an electron from a free atom in its basic energy state to infinity.
Links:
- Symbol:
IE_h- Latex:
\(\mathrm{IE}_\text{H}\)
- Dimension:
energy
- solar_mass¶
The solar
massis a standard unit of mass in astronomy approximately equal to the mass of the Sun. The relative uncertainty of the measurement is \(4 \cdot 10^{-5}\).Links:
- Symbol:
M_Sun- Latex:
\(M_\odot\)
- Dimension:
mass
- earth_mass¶
The Earth
massis a standard unit of mass in astronomy equal to the mass of the planet Earth. The relative uncertainty of the measurement is \(10^{-4}\).Links:
- Symbol:
M_Earth- Latex:
\(M_\oplus\)
- Dimension:
mass
- boltzmann_constant¶
The Boltzmann constant is the proportionality factor that relates the average relative thermal energy of particles in a gas with the thermodynamic temperature of the gas.
Links:
- Symbol:
k_B- Latex:
\(k_\text{B}\)
- Dimension:
energy/temperature
- molar_gas_constant¶
The gas constant is the constant of proportionality that relates the energy scale in physics to the temperature scale and the scale used for amount of substance. It is molar equivalent to the
boltzmann_constant.Links:
- Symbol:
R- Latex:
\(R\)
- Dimension:
energy/(amount_of_substance*temperature)
- speed_of_light¶
The speed of light in vacuum is a universal physical constant that is exactly equal to \(299 \, 792 \, 458\) metres per second.
Links:
- Symbol:
c- Latex:
\(c\)
- Dimension:
velocity
- vacuum_permittivity¶
Vacuum permittivity, also known as permittivity of free space or the electric constant, is the value of the absolute dielectric permittivity of classical vacuum.
Links:
- Symbol:
epsilon_0- Latex:
\(\varepsilon_0\)
- Dimension:
capacitance/length
- vacuum_permeability¶
Vacuum permeability, also known as permeability of free space of the magnetic constant, is the value of the absolute permeability of classical vacuum.
Links:
- Symbol:
mu_0- Latex:
\(\mu_0\)
- Dimension:
force/current**2
- elementary_charge¶
Elementary charge is a fundamental physical constant defined as the electric charge carried by a single proton or, equivalently, the magnitude of the negative charge carried by a single electron.
Links:
- Symbol:
e- Latex:
\(e\)
- Dimension:
charge
- hbar¶
Reduced Planck constant is a modified version of the Planck constant used in the description of Quantum Mechanics.
Links:
- Symbol:
hbar- Latex:
\(\hbar\)
- Dimension:
action
- planck¶
The Planck constant is a fundamental physical constant of foundational importance in quantum mechanics. It is the constant of proportionality between a photon’s energy and frequency.
Links:
- Symbol:
h- Latex:
\(h\)
- Dimension:
action
- avogadro_constant¶
The Avogadro constant is an SI defining constant defined as the number of constituent particles per mole.
Links:
- Symbol:
N_A- Latex:
\(N_\text{A}\)
- Dimension:
1/amount_of_substance
- acceleration_due_to_gravity¶
A conventional standard value of the gravitational acceleration at Earth’s surface.
Links:
- Symbol:
g- Latex:
\(g\)
- Dimension:
acceleration
- stefan_boltzmann_constant¶
The Stefan—Boltzmann constant is the constant of proportionality between radiant exitance and black body’s temperature in the Stefan—Boltzmann law.
Links:
- Symbol:
sigma- Latex:
\(\sigma\)
- Dimension:
energy/(length**2*temperature**4*time)
- richardson_constant¶
Constant of proportionality proposed by Richardson to describe the law of thermionic emission.
Links:
- Symbol:
a- Latex:
\(a\)
- Dimension:
current/(length**2*temperature**2)
- rydberg_frequency¶
In spectroscopy, the Rydberg constant is a physical constant relating to the electromagnetic spectra of an atom.
Links:
- Symbol:
R_H- Latex:
\(R_\text{H}\)
- Dimension:
frequency
- wien_displacement_constant¶
A constant of proportionality in Wien’s displacement law.
Links:
- Symbol:
b- Latex:
\(b\)
- Dimension:
action*temperature*velocity/energy
- gravitational_constant¶
The gravitational constant is a physical constant used in calculating the gravitational attraction between two objects.
Links:
- Symbol:
G- Latex:
\(G\)
- Dimension:
length**3/(mass*time**2)
- hubble_constant¶
The Hubble’s constant is the proportionality constant between the recessional velocity and the proper distance between the galaxy and the observer in the Hubble’s law. Its exact value is up to debate, however, the fundamental theory gives the number \(7%\) per billion years.
Links:
- Symbol:
H- Latex:
\(H\)
- Dimension:
1/time
- zero_point_luminosity¶
Zero-point luminosity is a constant defined relative to a star for calibrating perposes. The value given here has been defined by the International Astronomical Union (IAU).
Links:
- Symbol:
L_0- Latex:
\(L_0\)
- Dimension:
power
- sun_luminosity¶
luminosityof the Sun.- Symbol:
L_Sun- Latex:
\(L_\odot\)
- Dimension:
power
- faraday_constant¶
The Faraday constant represents the amount of electric charge carried by one mole, or Avogadro’s number, of electrons.
Links:
- Symbol:
F- Latex:
\(\mathfrak{F}\)
- Dimension:
charge/amount_of_substance