1 package org.djunits.value.vfloat.scalar.base; 2 3 import org.djunits.unit.DimensionlessUnit; 4 import org.djunits.unit.ElectricalChargeUnit; 5 import org.djunits.value.vdouble.scalar.Dimensionless; 6 import org.djunits.value.vdouble.scalar.ElectricalCharge; 7 import org.djunits.value.vdouble.scalar.Frequency; 8 import org.djunits.value.vdouble.scalar.Mass; 9 import org.djunits.value.vdouble.scalar.SIScalar; 10 import org.djunits.value.vdouble.scalar.Speed; 11 12 /** 13 * Various physical constants. For many, see 14 * <a href="https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_base_units">Wikipedia 2019 redefinition of the SI base 15 * units</a> 16 * @author <a href="https://www.tudelft.nl/staff/p.knoppers">Peter Knoppers</a> 17 */ 18 public final class FloatConstants 19 { 20 /** Utility class. */ 21 private FloatConstants() 22 { 23 // utility class 24 } 25 26 /** 27 * Number of constituent particles in a Mole; a.k.a. Avogadro's number. This value is exact since the 2019 redefinition of 28 * the SI base units. 29 */ 30 public static final SIScalar AVOGADRO = SIScalar.of(6.02214076e23, "1/mol"); 31 32 /** 33 * Boltzmann constant in Joule per Kelvin (this value is exact since the 2019 redefinition of SI base units). See 34 * <a href="https://en.wikipedia.org/wiki/Boltzmann_constant">Wikipedia: Boltzmann constant</a> 35 */ 36 public static final SIScalar BOLTZMANN = SIScalar.of(1.380649e-23, "kgm2/s2K"); 37 38 /** 39 * The Cesium 133 ground state hyperfine structure transition frequency. This value is exact since the 2006 redefinition of 40 * the SI base units. 41 */ 42 public static final Frequency CESIUM133_FREQUENCY = Frequency.of(9192631770d, "1/s"); 43 44 /** Electrical charge of one electron. This value is exact since the 2019 redefinition of the SI base units. */ 45 public static final ElectricalCharge ELECTRONCHARGE = new ElectricalCharge(-1, ElectricalChargeUnit.ATOMIC_UNIT); 46 47 /** 48 * Mass of an electron. See <a href="https://en.wikipedia.org/wiki/Physical_constant">Wikipedia Physical constant</a>. This 49 * value of this physical constant has an uncertainty of 2.8e-40 kg. 50 */ 51 public static final Mass ELECTRONMASS = Mass.of(9.1093837015e-31, "kg"); 52 53 /** ElectricalCharge of one proton. */ 54 public static final ElectricalCharge PROTONCHARGE = new ElectricalCharge(1, ElectricalChargeUnit.ATOMIC_UNIT); 55 56 /** 57 * Mass of a neutron. See <a href="https://en.wikipedia.org/wiki/List_of_physical_constants">Wikipedia List of physical 58 * constants</a>. This value of this physical constant has an uncertainty of 9.5e-37 kg. 59 */ 60 public static final Mass NEUTRONMASS = Mass.of(1.6749274714e-27, "kg"); 61 62 /** 63 * Mass of a proton. See <a href="https://en.wikipedia.org/wiki/Physical_constant">Wikipedia Physical constant</a>. This 64 * value of this physical constant has an uncertainty of 5.1e-37. 65 */ 66 public static final Mass PROTONMASS = Mass.of(1.67262192369e-27, "kg"); 67 68 /** 69 * Gravitational constant, a.k.a. Newtonian constant of gravitation. This is the 2018 best known approximation, which has an 70 * uncertainty 1.5e-15 m^3/kgs^2 71 */ 72 public static final SIScalar G = SIScalar.of(6.67430e-11, "m3/kgs2"); 73 74 /** Speed of light in vacuum. This value is exact (since the 2006 redefinition of the SI base units). */ 75 public static final Speed LIGHTSPEED = Speed.of(299792458, "m/s"); 76 77 /** 78 * Permeability of vacuum. See <a href="https://en.wikipedia.org/wiki/Vacuum_permeability">Wikipedia, Vacuum 79 * permeability</a>. The uncertainty of this value is 1.9e-16N/A^2. 80 */ 81 public static final SIScalar VACUUMPERMEABILITY = SIScalar.of(1.25663706212e-6, "kgm/s2A2"); 82 83 /** 84 * Permittivity of vacuum. See <a href="https://en.wikipedia.org/wiki/Vacuum_permittivity">Wikipedia Vacuum 85 * permittivity</a>. The uncertainty of this value is 1.3e-21 F/m. 86 */ 87 public static final SIScalar VACUUMPERMITTIVITY = SIScalar.of(8.8541878128e-12, "s4A2/kgm3"); 88 89 /** Impedance of vacuum. */ 90 public static final SIScalar VACUUMIMPEDANCE = VACUUMPERMEABILITY.times(LIGHTSPEED); 91 92 /** 93 * Planck constant; ratio of a photon's energy and its frequency. This value is exact since the 2019 redefinition of the SI 94 * base units. 95 */ 96 public static final SIScalar PLANCK = SIScalar.of(6.62607015e-34, "kgm2/s"); 97 98 /** 99 * The luminous efficacy Kcd of monochromatic radiation of frequency 540×10^12 Hz (540 THz). This is the frequency of a 100 * green-colored light at approximately the peak sensitivity of the human eye. This value is exact since the 2006 101 * redefinition of the SI base units. 102 */ 103 public static final SIScalar LUMINOUS_EFFICACY_540THZ = SIScalar.of(683d, "cdsrs3/kg"); 104 105 /** Ratio of circumference of circle and its radius. */ 106 public static final Dimensionless TAU = new Dimensionless(Math.PI * 2, DimensionlessUnit.SI); 107 108 /** Reduced Planck constant, a.k.a. angular Planck constant; Planck constant divided by 2 pi. */ 109 public static final SIScalar PLANKREDUCED = PLANCK.divide(TAU); 110 111 }