Physical constant

A physical constant, sometimes fundamental physical constant or universal constant, is a physical quantity that is generally believed to be both universal in nature and have constant value in time. It is contrasted with a mathematical constant, which has a fixed numerical value, but does not directly involve any physical measurement.

Comment
enA physical constant, sometimes fundamental physical constant or universal constant, is a physical quantity that is generally believed to be both universal in nature and have constant value in time. It is contrasted with a mathematical constant, which has a fixed numerical value, but does not directly involve any physical measurement.
DifferentFrom
Dimensionless physical constant
Has abstract
enA physical constant, sometimes fundamental physical constant or universal constant, is a physical quantity that is generally believed to be both universal in nature and have constant value in time. It is contrasted with a mathematical constant, which has a fixed numerical value, but does not directly involve any physical measurement. There are many physical constants in science, some of the most widely recognized being the speed of light in a vacuum c, the gravitational constant G, the Planck constant h, the electric constant ε0, and the elementary charge e. Physical constants can take many dimensional forms: the speed of light signifies a maximum speed for any object and its dimension is length divided by time; while the fine-structure constant α, which characterizes the strength of the electromagnetic interaction, is dimensionless. The term fundamental physical constant is sometimes used to refer to universal-but-dimensioned physical constants such as those mentioned above. Increasingly, however, physicists only use fundamental physical constant for dimensionless physical constants, such as the fine-structure constant α. Physical constant, as discussed here, should not be confused with other quantities called "constants", which are assumed to be constant in a given context without being fundamental, such as the "time constant" characteristic of a given system, or material constants (e.g., Madelung constant, electrical resistivity, and heat capacity). Since May 2019, all of the SI base units have been defined in terms of physical constants. As a result, five constants: the speed of light in vacuum, c; the Planck constant, h; the elementary charge, e; the Avogadro constant, NA; and the Boltzmann constant, kB, have known exact numerical values when expressed in SI units. The first three of these constants are fundamental constants, whereas NA and kB are of a technical nature only: they do not describe any property of the universe, but instead only give a proportionality factor for defining the units used with large numbers of atomic-scale entities.
Hypernym
Quantity
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Physical constant
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enPhysical constant
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Age of the universe
Anthropic principle
Arnold Sommerfeld
Arthur Eddington
Atomic physics
Avogadro constant
Boltzmann constant
Cabibbo–Kobayashi–Maskawa matrix
Category:Empirical laws
Category:Measurement
Category:Physical constants
Category:Physical quantities
Category:Scientific laws
Classical electromagnetism
Constant (mathematics)
Coulomb constant
Dimensional analysis
Dimensionless
Dimensionless physical constant
Eddington number
Electrical resistivity and conductivity
Electric constant
Electromagnetic interaction
Electromagnetism
Electron
Electron rest mass
Elementary charge
Elementary particles
Fine-structure constant
Fine-tuned universe
Gauge group
General relativity
Gravitational constant
Hartree atomic units
Heat capacity
Higgs field
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International prototype of the kilogram
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Josephson constant
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List of common physics notations
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List of physical constants
Madelung constant
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Paul Dirac
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Planck constant
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Rydberg constant
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Standard Model (mathematical formulation)
The speed of light
Time
Time constant
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Type Ia supernovae
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Variable speed of light
Von Klitzing constant
Weinberg angle
Yukawa couplings
SameAs
4155639-2
4174607-7
Constantă fizică
Constante física
Constante física
Constante física
Constante physique
Constant física
Costante fisica
Custanti fìsica
Fizičke konstante
Fizikai állandó
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Fizikāla konstante
Fizikalna konstanta
Fizikalna konstanta
Fizikalne konstante
Fizikalne konstante
Fizik doimiylar
Fiziki sabitlər
Fiziksel sabit
Füüsikakonstant
Fysikalisk konstant
Fysiske konstanter
Fysisk konstant
Fysisk konstant
Fyzikální konstanty
Hằng số vật lý
hSTN
Konstanta fisika
Luonnonvakio
m.05s1s
Natuurkundige constante
Natuurkundige konstante
Pemalar fizik
Physical constant
Physical constant
Physical constant
Physikalische Konstante
Physikalische Konstantn
Q173227
Stałe fizyczne
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Φυσική σταθερά
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Фундаментальные физические постоянные
Фундаментальныя фізічныя пастаянныя
Фундаменталь физик даимиләр
Фізичні константи
Ֆիզիկական հաստատուններ
קבוע פיזיקלי
ثابت فيزيائي
ثابت فیزیکی
نەگۆڕی فیزیکی
भौतिक नियतांक
ভৌত ধ্রুবক
ਭੌਤਿਕੀ ਸਥਿਰਾਂਕ
இயற்பியல் மாறிலி
ค่าคงตัวทางฟิสิกส์
ფიზიკური მუდმივა
物理定数
物理常數
물리 상수
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Category:Empirical laws
Category:Measurement
Category:Physical constants
Category:Physical quantities
Category:Scientific laws
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