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physical_constants
is a collection of physical constants,
copied from CODATA 2006 recommended values
(https://physics.nist.gov/cuu/Constants/).
load ("physical_constants")
loads this package,
and loads ezunits
also, if it is not already loaded.
A physical constant is represented as a symbol which has a property
which is the constant value.
The constant value is a dimensional quantity, as represented by ezunits
.
The function constvalue
fetches the constant value;
the constant value is not the ordinary value of the symbol,
so symbols of physical constants persist in evaluated expressions until their
values are fetched by constvalue
.
physical_constants
includes some auxiliary information,
namely, a description string for each constant,
an estimate of the error of its numerical value,
and a property for TeX display.
To identify physical constants, each symbol has the
physical_constant
property;
propvars(physical_constant)
therefore shows the list
of all such symbols.
physical_constants
comprises the following constants.
%c
speed of light in vacuum
%mu_0
magnetic constant
%e_0
electric constant
%Z_0
characteristic impedance of vacuum
%G
Newtonian constant of gravitation
%h
Planck constant
%h_bar
Planck constant
%m_P
Planck mass
%T_P
Planck temperature
%l_P
Planck length
%t_P
Planck time
%%e
elementary charge
%Phi_0
magnetic flux quantum
%G_0
conductance quantum
%K_J
Josephson constant
%R_K
von Klitzing constant
%mu_B
Bohr magneton
%mu_N
nuclear magneton
%alpha
fine-structure constant
%R_inf
Rydberg constant
%a_0
Bohr radius
%E_h
Hartree energy
%ratio_h_me
quantum of circulation
%m_e
electron mass
%N_A
Avogadro constant
%m_u
atomic mass constant
%F
Faraday constant
%R
molar gas constant
%%k
Boltzmann constant
%V_m
molar volume of ideal gas
%n_0
Loschmidt constant
%ratio_S0_R
Sackur-Tetrode constant (absolute entropy constant)
%sigma
Stefan-Boltzmann constant
%c_1
first radiation constant
%c_1L
first radiation constant for spectral radiance
%c_2
second radiation constant
%b
Wien displacement law constant
%b_prime
Wien displacement law constant
Reference: https://physics.nist.gov/cuu/Constants/
Examples:
The list of all symbols which have the physical_constant
property.
(%i1) load ("physical_constants")$ (%i2) propvars (physical_constant); (%o2) [%c, %mu_0, %e_0, %Z_0, %G, %h, %h_bar, %m_P, %T_P, %l_P, %t_P, %%e, %Phi_0, %G_0, %K_J, %R_K, %mu_B, %mu_N, %alpha, %R_inf, %a_0, %E_h, %ratio_h_me, %m_e, %N_A, %m_u, %F, %R, %%k, %V_m, %n_0, %ratio_S0_R, %sigma, %c_1, %c_1L, %c_2, %b, %b_prime]
Properties of the physical constant %c
.
(%i1) load ("physical_constants")$ (%i2) constantp (%c); (%o2) true (%i3) get (%c, description); (%o3) speed of light in vacuum (%i4) constvalue (%c); m (%o4) 299792458 ` - s (%i5) get (%c, RSU); (%o5) 0 (%i6) tex (%c); $$c$$ (%o6) false
The energy equivalent of 1 pound-mass.
The symbol %c
persists until its value is fetched by constvalue
.
(%i1) load ("physical_constants")$ (%i2) m * %c^2; 2 (%o2) %c m (%i3) %, m = 1 ` lbm; 2 (%o3) %c ` lbm (%i4) constvalue (%); 2 lbm m (%o4) 89875517873681764 ` ------ 2 s (%i5) E : % `` J; Computing conversions to base units; may take a moment. 366838848464007200 (%o5) ------------------ ` J 9 (%i6) E `` GJ; 458548560580009 (%o6) --------------- ` GJ 11250000 (%i7) float (%); (%o7) 4.0759872051556356e+7 ` GJ
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