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5.2.2  Constants Library

The physical constants are in the Phys menu, Constant sub-menu. The following table gives the Constants Library :

NameDescription
_NA_Avogadro’s number
_k_Boltzmann constant
_Vm_Molar volume
_R_Universal gas constant
_StdT_Standard temperature
_StdP_Standard pressure
_sigma_Stefan-Boltzmann constant
_c_Speed of light in vacuum
_epsilon0_Permittivity of vacuum
_mu0_Permeability of vacuum
_g_Acceleration of gravity
_G_Gravitational constant
_h_Planck’s constant
_hbar_Dirac’s constant
_q_Electron charge
_me_Electron rest mass
_qme_q/me (Electron charge/masse)
_mp_Proton rest mass
_mpme_mp/me (proton masse/electron masse)
_alpha_Fine structure constant
_phi_Magnetic flux quantum
_F_Faraday constant
_Rinfinity_Rydberg constant
_a0_Bohr radius
_muB_Bohr magneton
_muN_Nuclear magneton
_lambda0_Photon wavelength (ch/e)
_f0_Photon frequency (e/h)
_lambdac_Compton wavelength
_rad_1 radian
_twopi_2*pi radians
_angl_180 degrees angle
_c3_Wien displacement constant
_kq_k/q (Boltzmann/electron charge)
_epsilon0q_epsilon0/q (permitivity /electron charge)
_qepsilon0_q*epsilon0 (electron charge *permitivity)
_epsilonsi_Silicium dielectric constant
_epsilonox_Bioxyd of silicium dielectric constant
_I0_Reference intensity

To have the value of a constant, input the constant name in the command line of Xcas and valid with enter (don’t forget to put _ at the begining and at the end of the constant name).


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