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

Name | Description |

_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_ | Permitivity 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/mass) |

_mp_ | Proton rest mass |

_mpme_ | mp/me (proton mass/electron mass) |

_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 evaluate with enter (don’t forget to put _ at the beginning and at the end of the constant name).