1 package org.djunits.value.vdouble.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 * <p>
14 * Various physical constants. For many, see
15 * <a href="https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_base_units">Wikipedia 2019 redefinition of the SI base
16 * units</a>
17 * </p>
18 * @author <a href="https://www.tudelft.nl/staff/p.knoppers">Peter Knoppers</a>
19 */
20 public final class Constants
21 {
22 /** Utility class. */
23 private Constants()
24 {
25 // utility class
26 }
27
28 /**
29 * Number of constituent particles in a Mole; a.k.a. Avogadro's number. This value is exact since the 2019 redefinition of
30 * the SI base units.
31 */
32 public static final SIScalar AVOGADRO = SIScalar.of(6.02214076e23, "1/mol");
33
34 /**
35 * Boltzmann constant in Joule per Kelvin (this value is exact since the 2019 redefinition of SI base units). See
36 * <a href="https://en.wikipedia.org/wiki/Boltzmann_constant">Wikipedia: Boltzmann constant</a>
37 */
38 public static final SIScalar BOLTZMANN = SIScalar.of(1.380649e-23, "kgm2/s2K");
39
40 /**
41 * The Cesium 133 ground state hyperfine structure transition frequency. This value is exact since the 2006 redefinition of
42 * the SI base units.
43 */
44 public static final Frequency CESIUM133_FREQUENCY = Frequency.of(9192631770d, "1/s");
45
46 /** Electrical charge of one electron. This value is exact since the 2019 redefinition of the SI base units. */
47 public static final ElectricalCharge ELECTRONCHARGE = new ElectricalCharge(-1, ElectricalChargeUnit.ATOMIC_UNIT);
48
49 /**
50 * Mass of an electron. See <a href="https://en.wikipedia.org/wiki/Physical_constant">Wikipedia Physical constant</a>. This
51 * value of this physical constant has an uncertainty of 2.8e-40 kg.
52 */
53 public static final Mass ELECTRONMASS = Mass.of(9.1093837015e-31, "kg");
54
55 /** ElectricalCharge of one proton. */
56 public static final ElectricalCharge PROTONCHARGE = new ElectricalCharge(1, ElectricalChargeUnit.ATOMIC_UNIT);
57
58 /**
59 * Mass of a neutron. See <a href="https://en.wikipedia.org/wiki/List_of_physical_constants">Wikipedia List of physical
60 * constants</a>. This value of this physical constant has an uncertainty of 9.5e-37 kg.
61 */
62 public static final Mass NEUTRONMASS = Mass.of(1.6749274714e-27, "kg");
63
64 /**
65 * Mass of a proton. See <a href="https://en.wikipedia.org/wiki/Physical_constant">Wikipedia Physical constant</a>. This
66 * value of this physical constant has an uncertainty of 5.1e-37.
67 */
68 public static final Mass PROTONMASS = Mass.of(1.67262192369e-27, "kg");
69
70 /**
71 * Gravitational constant, a.k.a. Newtonian constant of gravitation. This is the 2018 best known approximation, which has an
72 * uncertainty 1.5e-15 m^3/kgs^2
73 */
74 public static final SIScalar G = SIScalar.of(6.67430e-11, "m3/kgs2");
75
76 /** Speed of light in vacuum. This value is exact (since the 2006 redefinition of the SI base units). */
77 public static final Speed LIGHTSPEED = Speed.of(299792458, "m/s");
78
79 /**
80 * Permeability of vacuum. See <a href="https://en.wikipedia.org/wiki/Vacuum_permeability">Wikipedia, Vacuum
81 * permeability</a>. The uncertainty of this value is 1.9e-16N/A^2.
82 */
83 public static final SIScalar VACUUMPERMEABILITY = SIScalar.of(1.25663706212e-6, "kgm/s2A2");
84
85 /**
86 * Permittivity of vacuum. See <a href="https://en.wikipedia.org/wiki/Vacuum_permittivity">Wikipedia Vacuum
87 * permittivity</a>. The uncertainty of this value is 1.3e-21 F/m.
88 */
89 public static final SIScalar VACUUMPERMITTIVITY = SIScalar.of(8.8541878128e-12, "s4A2/kgm3");
90
91 /** Impedance of vacuum. */
92 public static final SIScalar VACUUMIMPEDANCE = VACUUMPERMEABILITY.times(LIGHTSPEED);
93
94 /**
95 * Planck constant; ratio of a photon's energy and its frequency. This value is exact since the 2019 redefinition of the SI
96 * base units.
97 */
98 public static final SIScalar PLANCK = SIScalar.of(6.62607015e-34, "kgm2/s");
99
100 /**
101 * The luminous efficacy Kcd of monochromatic radiation of frequency 540×10^12 Hz (540 THz). This is the frequency of a
102 * green-colored light at approximately the peak sensitivity of the human eye. This value is exact since the 2006
103 * redefinition of the SI base units.
104 */
105 public static final SIScalar LUMINOUS_EFFICACY_540THZ = SIScalar.of(683d, "cdsrs3/kg");
106
107 /** Ratio of circumference of circle and its radius. */
108 public static final Dimensionless TAU = new Dimensionless(Math.PI * 2, DimensionlessUnit.SI);
109
110 /** Reduced Planck constant, a.k.a. angular Planck constant; Planck constant divided by 2 pi. */
111 public static final SIScalar PLANKREDUCED = PLANCK.divide(TAU);
112
113 }