Physical constants and other data
Fundamental Physical Constants
There is a large number of physical constants and fundamental that are used in physics and electronics engineering.
These constants can be used in a variety of electronics calculations and may be very useful on occasions. Although not widely used in electronics design, they may nevertheless be used on occasions.
A physical constant is a quantity that is generally believed to be universal in nature and constant over time. In other words, apart from improvements in measurement accuracies, it will remain the same.
These physical constants appear in many areas of science and they take many forms.
Common examples of some fundamental physical constants are the speed of light in a vacuum and it has the dimensions of speed, i.e. length divided by time. Other physical constants have different dimensions, or some can be dimensionless.
Physical constant groupings
In order to be able to refer to the different physical constants and fundamental constants more easily, we have split them into different groups as seen below:
- Universal constants: Universal constants are those which are used in many areas of science. They include some of the fundamental constants such as the speed of light, permittivity and permeability in a vacuum, gravitational forces and Planck's constant.
- Electromagnetic constants: The electromagnetic constants are those constants within the overall physical constants that pertain to electromagnetic aspects. They include such items as the elementary charge, magnetic flux quantum, the Josephson frequency-voltage quotient and the like.
- Atomic constants: There are many fundamental physical constants associated with atomic level physics, etc. These atomic constants include values such as Rydberg constant, Bohr radius, Hartree energy, etc
- Electron constants: There are many physical or fundamental constants associated with electrons. These electron constants include values such as electron specific charge, electron molar mass, electron specific charge, etc.
- Proton constants: These physical constants are applicable to proton characteristics and include characteristics such as proton mass, proton specific charge, proton molar mass, proton magnetic moment etc.
- Neutron constants: These physical constants are related to neutrons, and include parameters such as neutron mass, neutron-electron mass ratio, neutron molar mass, etc..
- Physicochemical constants & parameters: These physical constants include parameters related to physic-chemical characteristics and include items such as Avagadro constant, Faraday constant, Boltzmann constant, standard atmosphere and many more.
Universal Constants
The universal constants are physical constants that are widely used in science.
The physical constants that come under the universal constants heading include items such as the speed of light, permeability of a vacuum, permittivity of a vacuum, Planck's constant and the Newtonian constant of gravity.
Details for these universal constants and more are given below. The constant name, symbol, value, units and the relative uncertainty are provided.
| CONSTANT NAME | SYMBOL OF CONSTANT | VALUE | UNITS | RELATIVE UNCERTAINTY |
|---|---|---|---|---|
| Speed of light in vacuum |
c
| 299 792 458 |
m/s
| |
| Permeability in a vacuum |
µ0
| 4π x 10^-7 = 12.566 370 614 |
N ⋅ A^-2
| |
| Permittivity in a vacuum |
ε0
| 1/(µ0 ⋅ c^2) 8.854 187 817 |
10^-12 F &sdot m^-1
| |
| Newtonian constant of gravitation |
G
| 6.672 59 |
10^-11 m^3 kg^-1 s^-1
| 128 |
| Planck constant |
h
| 6.626 0755 |
10^-34J⋅ s
| 0.60 |
| Planck's constant in electron volts |
h/{e}
| 4.135 6692 |
10^-15 eV s
| 0.30 |
| h/2π | 1.054 572 66 |
10^-34 J s
| 0.60 | |
| h/2π in electron volts | 6 582 1220 |
10^-16 eV s
| 0.30 | |
| Planck mass |
mp
| 2.176 71 |
10^-8 kg
| 64 |
| Planck length |
lp
| 1.616 05 |
10^-35m
| 64 |
| Planck time |
tp
| 5.390 56 |
10^-44s
| 64 |
Electromagnetic Constants
Electromagnetic constants are used in many areas of science and electronics for a variety of calculations.
The electromagnetic constants that come under the universal constants heading include items such as the elementary charge, magnetic flux quantum, Josephson frequency voltage quotient, etc.
Details for these electromagnetic constants and more are given below. The constant name, symbol, value, units and the relative uncertainty are provided.
| CONSTANT NAME | SYMBOL OF CONSTANT | VALUE | UNITS | RELATIVE UNCERTAINTY |
|---|---|---|---|---|
| Elementary charge |
e
| 1.602 177 33 |
10^-19 C
| 0.30 |
| Elementary charge |
e/h
| 2.417 988 36 |
10^14 A J^-1
| 0.30 |
| Magnetic flux quantum |
φ0
| 2.067 834 61 |
10^-15 Wb
| 0.30 |
| Josephson frequency-voltage quotient |
2e/h
| 4.835 9767 |
10^14 Hz V^-1
| 0.30 |
| Quantised Hall conductance |
e^2/h
| 3.784 046 14 | 0.045 | |
| Quantised Hall resistance |
RH
| 25.812 8056 |
Ω
| 0.045 |
| Bohr magneton |
µB
| 9.274 0154 |
10^-24 J T^-1
| 0.34 |
| Nuclear magneton |
µN
| 5.050 7866 |
10^-27 J T^-1
| 0.34 |
Atomic Constants
Atomic constants are used in many areas of science and electronics for a variety of calculations.
The atomic constants that come under the universal constants heading include items such as the Rydberg constant, Bohr radius, Hartree energy, etc.
Details for these atomic constants and more are given below. The constant name, symbol, value, units and the relative uncertainty are provided.
| CONSTANT NAME | SYMBOL OF CONSTANT | VALUE | UNITS | RELATIVE UNCERTAINTY |
|---|---|---|---|---|
| Rydberg constant |
R
| 10.973 731 534 |
m^-1
| 0.0012 |
| Rydberg constant in hertz | 3.289 841 9499 |
10^15 Hz
| 0.0012 | |
| Rydberg constant in Joules | 2.179 8741 |
10^-18 J
| 0.60 | |
| Rydberg constant in eV | 13.605 6981 |
eV
| 0.30 | |
| Bohr radius |
a0
| 0.529 177 249 |
10^-10 m
| 0.045 |
| Hartree energy |
Eh
| 4.359 748 2 |
10^-18 J
| 0.60 |
| Hartree energy in eV | 27.211 396 1 |
eV
| 0.30 | |
| Fine structure constant |
α
| 7.297 353 08 |
10^-3
| 0.045 |
| Inverse fine structure constant |
α^-1
| 137.035 989 5 | 0.045 |
Electron Constants
Electron constants are used in many areas of science and electronics for a variety of calculations.
The electron constants that come under the universal constants heading include items such as the electron specific charge, electron molar mass, electron specific charge, etc.
Details for these electron constants and more are given below. The constant name, symbol, value, units and the relative uncertainty are provided.
| CONSTANT NAME | SYMBOL OF CONSTANT | VALUE | UNITS | RELATIVE UNCERTAINTY |
|---|---|---|---|---|
| Electron mass |
Me
| 9.109 389 7 |
10^-37 kg
| 0.59 |
| Electron mass in electron volts | 0.510 999 06 |
MeV
| 0.30 | |
| Electron-proton mass ratio |
me/mp
| 5.446 170 13 |
10^-4
| 0.02 |
| Electron α particle mass ratio |
me/m&almpga;
| 1.370 933 54 |
10^-4
| 0.021 |
| Electron specific charge |
-e/me
| -1.758 819 62 |
10^11 C kg^-1
| 0.30 |
| Electron molar mass |
M(e)
| 5.485 799 03 |
10^-7 kg/mol
| 0.23 |
| Crompton wavelength |
λc
| 2.426 310 58 |
10^-12 m
| 0.089 |
| Classical electron radius |
re
| 2.817 940 92 |
10^-15 m
| 0.13 |
| Thomson cross section |
σe
| 0.665 246 16 |
10^-28 m^2
| 0.27 |
| Electron magnetic moment |
µe
| 928.477 01 |
10^-26 J T^-1
| 0.34 |
| Electron-proton magnetic moment ratio |
µe/µp
| 658.210 6881 | 0.010 |
Proton Constants
Proton constants are used in many areas of science and electronics for a variety of calculations.
The proton constants that come under the universal constants heading include items such as the proton mass, proton specific charge, proton molar mass, proton magnetic moment etc..
Details for these electron constants and more are given below. The constant name, symbol, value, units and the relative uncertainty are provided.
| CONSTANT NAME | SYMBOL OF CONSTANT | VALUE | UNITS | RELATIVE UNCERTAINTY |
|---|---|---|---|---|
| Proton mass |
mp
| 1.672 623 1 |
10^-27 kg
| 0.59 |
| Proton mass in electron volts | 938.272 31 |
MeV
| 0.30 | |
| Proton-electron mass ratio |
mp/me
| 1836.152 701 | 0.020 | |
| Proton specific charge |
e/mp
| 9.578 830 9 |
10^7 C kg^-1
| 0.30 |
| Proton molar mass |
Mp
| 1.007 276 470 |
10^-3 kg/mol
| 0.012 |
| Proton Crompton wavelength |
λc,p
| 1.321 410 02 |
10^-15 m
| 0.089 |
| Proton magnetic moment |
µp
| 1.410 607 61 |
10^-26 J T^-1
| 0.34 |
Neutron Constants
Neutron constants are used in many areas of science and electronics for a variety of calculations.
The neutron constants that come under the universal constants heading include items such as the neutron mass, neutron-electron mass ratio, neutron molar mass, etc..
Details for these neutron constants and more are given below. The constant name, symbol, value, units and the relative uncertainty are provided.
| CONSTANT NAME | SYMBOL OF CONSTANT | VALUE | UNITS | RELATIVE UNCERTAINTY |
|---|---|---|---|---|
| Neutron mass |
Mp
| 1.674 928 6 |
10^-27 kg
| 0.59 |
| Neutron mass in electron volts | 939.565 63 |
MeV
| 0.30 | |
| Neutron-electron mass ratio |
mn/me
| 1838.683 662 | 0.022 | |
| Neutron proton mass ratio |
mn/mp
| 1.001 378 404 | 0.009 | |
| Neutron molar mass |
Mn
| 1.008 664 904 |
10^-3 kg/mol
| 0.014 |
| Neutron Crompton wavelength |
λcn
| 1.319 591 |
10^-15m
| 0.014 |
| Neutron magnetic moment |
µn
| 0.996 237 07 |
10^-26 J T^-1
| 0.41 |
| Neutron electron magnetic moment ratio |
µn/µe
| 1.040 668 82 |
10^-3
| 0.24 |
| Neutron proton magnetic moment ratio |
µn/µp
| 0.684 979 34 | 0.24 |
Physico-Chemical Constants & Parameters
Physico-chemical constants parameters and properties are used in many areas of science and electronics for a variety of calculations.
The physicochemical parameters & properties that come under the universal constants heading include items such as the Avagadro constant, Faraday constant, Boltzmann constant, standard atmosphere and many more.
Details for these physico-chemical parameters and more are given below. The constant name, symbol, value, units and the relative uncertainty are provided.
| CONSTANT NAME | SYMBOL OF CONSTANT | VALUE | UNITS | RELATIVE UNCERTAINTY |
|---|---|---|---|---|
| Avagadro constant |
Na, L
| 6.022 136 7 |
10^23 mol^-1
| 0.59 |
| Atomic mass constant |
Mu
| 1.660 540 2 | 0.59 | |
| Atomic mass constant in electron volts | 931 494 32 |
MeV
| 0.30 | |
| Faraday constant |
F
| 96.485 309 |
C mol^-1
| 0.30 |
| Molar Planck constant |
Nah
| 3.990 313 23 |
10^-10 J s mol^-1
| 0.089 |
| Molar gas constant |
R
| 8.314 510 |
J mol^-1 K^-1
| 8.4 |
| Boltzmann consant |
k
| 1.380 658 |
10^-23 J K^-1
| 8.5 |
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