| Quantity |
Dimension |
Alternatives |
Definition/Notes |
| A: |
| Acceleration, angular |
s-2 |
rad.s-2 |
[ΔAngularVelocity]/[Time] |
| Abbé number |
1 |
Dimensionless |
Inverse of refractive index. |
| Absorbed radiation dose |
m2.s-2 |
J.kg-1, Gy (gray) |
[Energy]/[Mass] |
| Absorbed dose rate |
m2.s-3 |
Gy.s-1 |
[Absorbed dose]/[Time] |
| Acceleration, linear |
m.s-2 |
|
[ΔVelocity]/[Time] |
| Action |
kg.m2.s-1 |
J.s |
[Energy]*[Time], [Moment of motion]*[Distance] |
| Activity of radioactive source |
s-1 |
Bq (becquerel) |
[Events]/[Time] |
| Admittance, inductive |
kg-1.m-2.s3.A2 |
S (siemens) |
1/[Inductive impedance]. |
| Admittance, of a circuit |
kg-1.m-2.s3.A2 |
S (siemens) |
1/[Circuit impedance]. |
| Albedo, of a surface |
1 |
Dimensionless |
[Reflected elmag power]/[Incident elmag power] |
| Angular acceleration |
s-2 |
rad.s-2 |
[ΔAngularVelocity]/[Time] |
| Angular moment of inertia |
kg.m2 |
|
[Mass]*[Distance2] |
| Angular moment of motion |
kg.m2.s-1 |
J.s |
[Moment of motion]*[Distance]. Like [action]. |
| Angular velocity |
s-1 |
rad.s-1 |
[Plane angle]/[Time] |
| Annealing point |
K |
|
Temperature at which viscosity drops below 1012 Pa.s |
| Area |
m2 |
|
[Distance]*[Distance] |
| Attenuation |
m-1 |
dB/m |
[Ratio]/m. Applies to propagation. |
| B: |
| Bandwidth |
s-1 |
Hz |
[ΔFrequency] |
| Baud rate |
bit.s-1 |
baud |
[Information]/[Time]. Also: information flux. |
| Bulk modulus |
kg-1.m.s2 |
Pa-1 |
[Pressure]/([ΔVolume]/[Volume]). Same as compressibility . |
| C: |
| Capacitance, electric |
kg-1.m-2.s4.A2 |
C.V-1, F (farad) |
[Charge]/[ΔPotential] |
| Capacitive reactance |
kg.m2.s-3.A-2 |
Ω (ohm) |
1/(i[Angular frequency].[Capacitance]) |
| Capacitive susceptance |
kg-1.m-2.s3.A2 |
S (siemens) |
1/[Capacitive reactance]. |
| Circulation |
m2.s-1 |
J.s.kg-1 |
[Angular moment]/[Mass], [Velocity]*[Loop length] |
| Characteristic impedance |
kg.m2.s-3.A-2 |
V.A-1, Ω, ohm |
√([Mag.Permeability]/[El.Permittivity]) |
| Charge, electric |
s .A |
C (coulomb) |
[Current]*[Time] |
| Charge, quantum |
1 |
Dimensionless |
[Charge]/[Elementary charge quantum] |
| Charge, molecular/ionic, quantum |
1 |
Dimensionless |
[Charge of a molecule or ion]/[Elementary charge quantum] |
| Charge density |
m-3.s.A |
C.m-3 |
[Charge]/[Volume] |
| Charge/mass ratio |
kg-1.s.A |
C.kg-1 |
[Charge]/[Mass]. Same as specific charge |
| Charge, molar |
s.A.mol-1 |
C.mol-1 |
[Charge]/[Quantity] |
| Chemical potential, molar |
kg.m2.s-2.mol-1 |
J.mol-1 |
[ΔInternalEnergy]/[ΔQuantityOfSubstance] |
| Circuit admittance |
kg-1.m-2.s3.A2 |
S (siemens) |
1/[Circuit impedance]. |
| Circuit impedance |
kg.m2.s-3.A-2 |
Ω (ohm) |
|
| Collision cross section |
m2 |
|
[Distance]*[Distance]. Same as cross section |
| Compressibility |
kg-1.m.s2 |
Pa-1 |
[Pressure]/([ΔVolume]/[Volume]). Same as bulk modulus . |
| Compression |
kg.m-1.s-2 |
N.m-2, Pa (pascal) |
[Force]/[Area]. ... same as pressure |
| Compression modulus |
kg-1.m.s2 |
Pa-1 |
[Pressure]/([ΔVolume]/[Volume]). Same as compressibility . |
| Compressive strength |
kg.m-1.s-2 |
N.m-2, Pa |
[Force]/[Area]. Same dimension as pressure. |
| Concentration, molar |
m-3.mol |
|
[Quantity]/[Volume]. Same as molar density. |
| Concentration, by mass |
1 |
Dimensionless |
[Mass of substance]/[Total mass]. Same as mass concentration |
| Concentration, by volume |
1 |
Dimensionless |
[Volume of substance]/[Total volume]. Same as volume concentration . |
| Concentration, by weight |
1 |
Dimensionless |
[Mass of substance]/[Total mass]. Same as mass concentration |
| Conductance, electric |
kg-1.m-2.s3.A2 |
A.V-1, S (siemens) |
1/[Resistance]. |
| Conductivity, electric |
kg-1.m-3.s3.A2 |
S.m-1 |
1/[Resistivity] |
| Conductivity, molar |
kg-1.s3.A2.mol-1 |
S.m2.mol-1 |
[El.conductivity]/[Concentration] |
| Conductivity, thermal |
kg.m.s-3.K-1 |
W.m-1.K-1 |
[Heat flux]/([Distance]*[ΔTemperature]) |
| Constringence |
1 |
Dimensionless |
[Transversal striction]/[Londitudinal elongation]. |
| Convergence |
m-1 |
dioptry |
in optics, but not only ... |
| Count of events/instances |
1 |
|
This covers all kinds of enumerations. |
| Count rate |
s-1 |
|
[Events]/[Time] |
| Couple |
kg.m2.s-2 |
N.m |
2*[Force]*[Distance] for two non-aligned opposing forces. |
| Critical angle of repose |
rad |
or degree |
Steepest angle of a slope before a slide |
| Cross section |
m2 |
|
[Distance]*[Distance] |
| Cryoscopic constant |
kg.mol-1.K |
K/(mol/kg) |
[ΔTemperature]/[Molality] |
| Current, electric |
A |
A (ampere) |
|
| Current density (electric) |
m-2.A |
|
[Current]/[Area]. Same as current intensity. |
| Current intensity (electric) |
m-2.A |
|
[Current]/[Area]. Same as current density. |
| Current noise, variance nJ2 |
s.A2 |
A2/Hz |
[Current]2/[Bandwidth] |
| Curvature radius |
m |
|
of a line in plane/space or surface in space |
| D: |
| Density of electric charge |
m-3.s.A |
C.m-3 |
[Charge]/[Volume] |
| Density of electric current |
m-2.A |
|
[Current]/[Area]. Same as current intensity. |
| Density of energy |
kg.m-1.s-2 |
J.m-3 |
[Energy]/[Volume]. |
| Density of mass |
kg.m-3 |
|
[Mass]/[Volume]. Same as specific density. |
| Density of substance |
m-3.mol |
|
[Quantity]/[Volume]. Same as concentration. |
| Dielectric constant |
1 |
Dimensionless |
[Permittivity]/[Permittivity of vacuum]. Same as relative permittivity |
| Dielectric strength/rigidity |
kg.m.s-3.A-1 |
V.m-1 |
[ΔPotential]/[Distance]. Same as electric strength |
| Diffusion coefficient |
m2.s-1 |
|
[Distance2]/[Time]. |
| Diffusivity, thermal |
m2.s-1 |
|
([∂Temperatute]/[∂Time])/[∇2Temperature]. |
| Dipole moment, electric |
m.s.A |
C.m |
[Charge]*[Distance] |
| Dipole moment, magnetic |
m2.A |
J.T-1 |
[Current]*[Area] |
| Dispersive power |
1 |
Dimensionless |
Ratio of differences of refractive indices. |
| Dispersivity quotient |
m-1 |
|
[ΔRefractive index]/[ΔWavelength] |
| Distance |
m |
|
in all Euclidean n-dimensional spaces. |
| Dose of absorbed radiation |
m2.s-2 |
J.kg-1, Gy (gray) |
[Energy]/[Mass]. |
| Dose rate |
m2.s-3 |
Gy.s-1 |
[Absorbed dose]/[Time]. |
| Drift speed |
m.s-1 |
|
Steady-state speed of an object. . |
| Duration |
s |
s (second) |
|
| Dynamic viscosity |
kg.m-1.s-1 |
Pa.s |
([Force]/[Area])/[ΔVelocity] |
| E: |
| Ebullioscopic constant |
kg.mol-1.K |
K/(mol/kg) |
[ΔTemperature]/[Molality]. |
| Electric capacitance |
kg-1.m-2.s4.A2 |
C.V-1, F (farad) |
[Charge]/[ΔPotential] |
| Electric charge |
s .A |
C (coulomb) |
[Current]*[Time] |
| Electric conductance |
kg-1.m-2.s3.A2 |
A.V-1, S (siemens) |
[Current]/[ΔPotential]. Inverse of resistance. |
| Electric conductivity |
kg-1.m-3.s3.A2 |
S.m-1 |
1/[Resistivity]. |
| Electric conductivity, molar |
kg-1.s3.A2.mol-1 |
S.m2.mol-1 |
[El.conductivity]/[Concentration]. |
| Electric current |
A |
A (ampere) |
|
| Electric dipole moment |
m.s.A |
C.m |
[Charge]*[Distance] |
| Electric field strength |
kg.m.s-3.A-1 |
V.m-1 |
[ΔPotential]/[Distance]. Also called electric intensity |
| Electric field gradient |
kg.s-3.A-1 |
V.m-2 |
[ΔEl.field strength]/[Distance]. |
| Electric flux density |
m-2.s.A |
C.m-2 |
[Charge]/[Area]. Also called electric induction |
| Electric inductance |
kg.m2.s-2.A-2 |
V.s.A-1, H (henry) |
[ΔPotential]/[dCurrent/dt] |
| Electric induction |
m-2.s.A |
C.m-2 |
[Charge]/[Area]. More properly electric flux density |
| Electric intensity |
kg.m.s-3.A-1 |
V.m-1 |
[ΔPotential]/[Distance]. More properly electric field strength |
| Electric permittivity |
kg-1.m-3.s4.A2 |
F.m-1 |
[El.flux density]/[El.field strength]. |
| Electric permittivity, relative |
1 |
Dimensionless |
[Permittivity]/[Permittivity of vacuum]. Same as dielectric constant |
| Electric polarization |
m-2.s.A |
C.m-2 |
[Charge]/[Area]. Like electric flux density |
| Electric potential |
kg.m2.s-3.A-1 |
W.A-1, J.C-1, V (volt) |
[Power]/[Current], [Energy]/[Charge] |
| Electric quadrupole moment |
m2.s.A |
C.m2 |
[Electric dipole]*[Distance], [Electric charge]*[Distance2] |
| Electric resistance |
kg.m2.s-3.A-2 |
V.A-1, Ω (ohm) |
[ΔPotential]/[Current] |
| Electric resistivity |
kg.m3.s-3.A-2 |
Ω.m |
([Resistance]*[Length])/[Area]. |
| Electric strength |
kg.m.s-3.A-1 |
V.m-1 |
[ΔPotential]/[Distance]. Also called dielectric strength . |
| Electromagnetic vector potential |
kg.m.s-2.A-1 |
V.s.m-1, T.m |
[El.field strength]*[Time] or [Mag.flux density]*[Distance] |
| Electromotive force (emf) |
kg.m2.s-3.A-1 |
V |
[ΔPotential] |
| Electrostriction coefficient |
kg-2.m-2.s6.A2 |
m2.V-2 |
([ΔVolume]/[Volume])/[Electric field strength]2. |
| Emittance, luminous |
cd.sr.m-2 |
lm.m-2, lx (lux) |
[Luminous flux]/[Area]. Same as luminous exitance |
| Energy |
kg.m2.s-2 |
N.m, J (joule) |
[Force]*[Distance], [Power]*[Time]. |
| Energy, molar |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Energy]/[Quantity]. |
| Energy, specific |
m2.s-2 |
J.kg-1 |
[Energy]/[Mass]. |
| Energy density |
kg.m-1.s-2 |
J.m-3 |
[Energy]/[Volume]. |
| Energy flux |
kg.m2.s-3 |
J.s-1, W (watt) |
[ΔEnergy]/[ΔTime]. Same as power. |
| Enthalpy |
kg.m2.s-2 |
J |
Like energy and heat. |
| Enthalpy, molar |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Enthalpy]/[Quantity]. Like molar heat. |
| Enthalpy, specific |
m2.s-2 |
J.kg-1 |
[Enthalpy]/[Mass]. Like specific heat. |
| Entropy |
kg.m2.s-2.K-1 |
J.K-1 |
[ΔHeat]/[Temperature]. |
| Entropy, molar |
kg.m2.s-2.K-1.mol-1 |
J.K-1.mol-1 |
[Entropy]/[Quantity]. |
| Entropy, specific |
m2.s-2.K-1 |
J.K-1.kg-1 |
[Entropy]/[Mass]. |
| Evolution rate on log-scale |
s-1 |
|
d{ln(Q)}/dt = (dQ/dt)/Q. Also relative evolution rate |
| Expansion coefficient, thermal |
K-1 |
|
([ΔLength]/[Length])/[Temperature]. |
| Exposure |
kg-1.s.A |
C.kg-1 |
[Charge]/[Mass]. Used for ionising radiations. |
| Extinction coefficient |
m-1 |
dB/m |
Used for propagation of radiation. |
| F: |
| Fire point |
K |
|
Temperature at which ignited vapour keeps burning |
| Flash point |
K |
|
Temperature at which vapour can be kept burning |
| Force |
kg.m.s-2 |
N (newton) |
[Mass]*[Acceleration]. |
| Force, thermodynamic |
kg.m.s-2.mol-1 |
N/mol |
[ΔChemical potential]/[Distance]. |
| Free energy |
kg.m2.s-2 |
J |
Also Helmholtz function. Like energy. |
| Free energy, molar |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Free energy]/[Quantity]. Also molar Helmholtz function |
| Free energy, specific |
m2.s-2 |
J.kg-1 |
[Free energy]/[Mass]. Also specific Helmholtz function |
| Free enthalpy |
kg.m2.s-2 |
J |
Also Gibbs function. Like energy. |
| Free enthalpy, molar |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Free enthalpy]/[Quantity]. Also molar Gibbs function |
| Free enthalpy, specific |
m2.s-2 |
J.kg-1 |
[Free enthalpy]/[Mass]. Also specific Gibbs function |
| Frequency of waves or events |
s-1 |
Hz (hertz) |
|
| Frequency drift rate |
s-2 |
Hz.s-1 |
[ΔFrequency]/[Time]. |
| Friction |
kg.m.s-2 |
N (newton) |
Tangential force between two moving surfaces. |
| Friction coefficient |
1 |
Dimensionless |
[Tangential force]/[Normal force]. |
| Fugacity |
kg.m-1.s-2 |
Pa |
Effective pressure in real gases. |
| G: |
| Gain of a device |
1 |
Dimensionless |
[Output]/[Input], like-quantities ratio. Often in dB. |
| g-factor of a particle |
1 |
Dimensionless |
[Magnetic moment]/([Spin].[Bohr magneton]) |
| Gradient, of electric field |
kg.s-3.A-1 |
V.m-2 |
[ΔEl.field strength]/[Distance]. |
| Gradient, of magnetic field |
kg.m-1.s-2.A-1 |
T.m-1 |
[ΔMag.flux density]/[Distance]. |
| Gradient, thermal |
K.m-1 |
|
[ΔTemperature]/[Distance]. Same as temperature gradient |
| Gravitational field intensity |
m.s-2 |
|
[Force]/[Mass], [Acceleration]. Same as gravity |
| Gravitational field potential |
m2.s-2 |
|
[Energy]/[Mass]. |
| Gravity |
m.s-2 |
|
[Force]/[Mass], [Acceleration]. Same as grav. field intensity |
| Gyromagnetic ratio |
kg-1.s.A |
Hz.T-1 |
[Mag.moment]/[Angular moment of motion]. |
| H: |
| Half life |
s |
|
typically of a radioactive substance |
| Hamiltonian |
kg.m2.s-2 |
J |
[Force]*[Distance], [Power]*[Time]. Like energy |
| Hardness |
kg.m-1.s-2 |
N.m-2 |
[Force]/[Area]. Same as pressure. |
| Heat |
kg.m2.s-2 |
J |
Like energy. |
| Heat, molar |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Heat]/[Quantity]. |
| Heat, specific |
m2.s-2 |
J.kg-1 |
[Heat]/[Mass]. |
| Heat capacity |
kg.m2.s-2.K-1 |
J.K-1 |
[ΔHeat]/[ΔTemperature]. |
| Heat capacity, molar |
kg.m2.s-2.K-1.mol-1 |
J.K-1.mol-1 |
[Heat capacity]/[Quantity]. |
| Heat capacity, specific |
m2.s-2.K-1 |
J.K-1.kg-1 |
[Heat capacity]/[Mass]. |
| Heat | Thermal conductivity |
kg.m.s-3.K-1 |
W.m-1.K-1 |
[Heat flux]/([Distance]*[ΔTemperature]). |
| Heat flux |
kg.m2.s-3 |
J.s, W |
[ΔHeat]/[ΔTime]. Like power. |
| Heat flux density |
kg.s-3 |
W.m-2 |
[Heat flux]/[Area]. Same as irradiance. |
| I: |
| Illuminance |
cd.sr.m-2 |
lm.m-2, lx (lux) |
[Luminous flux]/[Area]. |
| Impact resistance |
kg.s-2 |
J.m-2 |
[Energy]/[Area] |
| Impedance, characteristic |
kg.m2.s-3.A-2 |
V.A-1, Ω, ohm |
√([Mag.Permeability]/[El.Permittivity]). |
| Impedance, inductive |
kg.m2.s-3.A-2 |
Ω (ohm) |
i[Angular frequency].[Inductance] |
| Impedance, of a circuit |
kg.m2.s-3.A-2 |
Ω (ohm) |
|
| Impulse |
kg.m.s-1 |
|
[ΔMoment of motion], [Force]*[ΔTime], [Mass]*[ΔVelocity]. |
| Inductance |
kg.m2.s-2.A-2 |
V.s.A-1, Wb.A-1, H (henry) |
[ΔPotential]/[dCurrent/dt], [Mag.flux]/[Current] |
| Induction, electric |
m-2.s.A |
C.m-2 |
[Charge]/[Area]. Same as electric flux density |
| Inductive admittance |
kg-1.m-2.s3.A2 |
S (siemens) |
1/[Inductive impedance]. |
| Inductive impedance |
kg.m2.s-3.A-2 |
Ω (ohm) |
i[Angular frequency].[Inductance] |
| Information |
bit-1 |
bit |
One bit is the elementary information quantum. |
| Information flux |
bit.s-1 |
baud |
[Information]/[Time]. Also called baud rate. |
| Intensity of electric current |
m-2.A |
|
[Current]/[Area]. Same as current density. |
| Internal energy |
kg.m2.s-2 |
J |
Like energy and heat. |
| Internal energy, molar |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Internal energy]/[Quantity]. Like molar heat. |
| Internal energy, specific |
m2.s-2 |
J.kg-1 |
[Internal energy]/[Mass]. Like specific heat. |
| Ion mobility |
kg-1.m-1.s2.A |
m2.s-1.V-1 |
[Velocity]/[Electric field strength] . |
| Ionic force (strength) |
m-3.mol |
|
Sum([Concentration]*[Ionic quantum charge]2). |
| Ionic quantum charge |
1 |
Dimensionless |
[Ion charge]/[Elementary charge quantum] |
| Ionic strength (force) |
m-3.mol |
|
Sum([Concentration]*[Ionic quantum charge]2). |
| Irradiance |
kg.s-3 |
W.m-2 |
[Heat flux]/[Area]. Same as heat flux density |
| J: |
| Joule-Thomson coefficient |
kg-1.m.s2.K |
K.Pa-1 |
[ΔTemperature]/[ΔPressure]. |
| K: |
| Katalytic activity |
mol.s-1 |
katal |
[ΔQuantity]/[Time]. Same as molar production rate |
| Kinematic viscosity |
m2.s-1 |
|
[Dynamic viscosity]/[Density] |
| K-space vector |
m-1 |
|
same as reciprocal space position. |
| L: |
| Lagrangian |
kg.m2.s-2 |
J |
[Force]*[Distance], [Power]*[Time]. Like energy |
| Length |
m |
m (meter) |
|
| Linear stiffness |
kg.s-2 |
N.m-1 |
[Force]/[Displacement]. ... of a structure |
| Logarithmic ratio logb(A/A') |
1 |
log in any base b |
Applicable to any ratio of like quantities. |
| Logarithmic ratio ln(A/A') |
1 |
Np (neper) |
Uses natural logarithm. |
| Logarithmic ratio Log(P/P')/10 |
1 |
dB (decibel) |
Uses base-10 logarithm. Aplies only to power P. |
| Logarithmic ratio Log(X/X')/20 |
1 |
dB (decibel) |
Aplies to voltages (X=V) and currents (X=I). |
| Logarithmic scale differential |
1 |
Dimensionless |
dQ/Q, d{ln(Q)}, for any quantity Q. Also relative differential |
| Luminance |
cd.m-2 |
|
[Luminosity]/[Area] |
| Luminosity |
cd |
cd (candle) |
Same as luminous intensity |
| Luminous coefficient |
1 |
Dimensionless |
[Luminous efficacy]/[683 lm/W]. Same as luminous efficiency |
| Luminous efficacy |
cd.sr.kg-1.m-1.s3 |
lm/W |
[Luminous flux]/[Power] |
| Luminous efficiency |
1 |
Dimensionless |
[Luminous efficacy]/[683 lm/W]. Same as luminous coefficient |
| Luminous emittance |
cd.sr.m-2 |
lm.m-2, lx (lux) |
[Luminous flux]/[Area]. Same as luminous exitance |
| Luminous energy |
cd.sr.s |
lm.s |
[Luminous flux]*[Time]. Also known as talbot |
| Luminous flux |
cd.sr |
lm (lumen) |
[Luminosity]*[Solid angle]. Same as luminous power |
| Luminous intensity |
cd |
cd (candle) |
Same as luminosity |
| Luminous power |
cd.sr |
lm (lumen) |
[Luminosity]*[Solid angle]. Same as luminous flux |
| M: |
| Magnetic dipole moment |
m2.A |
J.T-1 |
[Current]*[Area]. Same as magnetic moment. |
| Magnetic field gradient |
kg.m-1.s-2.A-1 |
T.m-1 |
[ΔMag.flux density]/[Distance]. |
| Magnetic field strength |
m-1.A |
|
[Current]/[Distance]. Also called magnetic intensity |
| Magnetic flux |
kg.m2.s-2.A-1 |
V.s, W.s.A-1, Wb (weber) |
[ΔPotential]*[Time], [Power]/[dCurrent/dt] |
| Magnetic flux density |
kg.s-2.A-1 |
Wb.m-2, T (tesla) |
[Mag.flux]/[Area]. Also called magnetic induction |
| Magnetic induction |
kg.s-2.A-1 |
Wb.m-2, T (tesla) |
[Mag.flux]/[Area]. More properly magnetic flux density |
| Magnetic intensity |
m-1.A |
|
[Current]/[Distance]. More properly magnetic field strength |
| Magnetic moment |
m2.A |
J.T-1 |
[Current]*[Area] |
| Magnetic permeability |
kg.m.s-2.A-2 |
H.m-1 |
[Mag.flux density]/[Mag.field strength]. |
| Magnetic permeability, relative |
1 |
Dimensionless |
[Permeability]/[Permeability of vacuum]. |
| Magnetic quadrupole moment |
m3.A |
m.J.T-1 |
[Mag.dipole]*[Distance] |
| Magnetic susceptibility |
1 |
Dimensionless |
[Relative permeability]-1. |
| Magnetization |
m-1.A |
|
[Mag.moment]/[Volume]. Like magnetic field strength |
| Magnetogyric ratio |
kg.s-1.A-1 |
T.Hz-1 |
[Angular moment of motion]/[Mag.moment]. |
| Magnetomotive force (mmf) |
A |
|
[Current]*[Number of turns] |
| Magnitude of a star |
1 |
Dimensionless |
m-m'=-100.4(S/S'), where S,S' are the luminous fluxes of two stars |
| Mass |
kg |
kg (kilogram) |
|
| Mass density |
kg.m-3 |
|
[Mass]/[Volume]. Same as specific density. |
| Mass concentration |
1 |
Dimensionless |
[Mass of substance]/[Total mass]. Also concentration by weight |
| Mass flow |
kg.s-1 |
kg |
[ΔMass]/[Time]. Same as mass production rate |
| Mass production rate |
kg.s-1 |
|
[ΔMass]/[Time]. Same as mass flow. |
| Mass, molar |
kg.mol-1 |
|
[Mass]/[Quantity] |
| Mean anomaly |
1 |
Dimensionless |
Of an body on a Kepler orbit; t.sqrt(G(M1+M2)/r3) |
| Mean motion |
s-1 |
|
Of an body on a Kepler orbit; sqrt(G(M1+M2)/r3) |
| Modulus of compression |
kg-1.m.s2 |
Pa-1 |
[Pressure]/([ΔVolume]/[Volume]). Same as compressibility 3 |
| Modulus of rigidity |
kg.m.s-2 |
N, N.rad-1 |
[Force]/[ΔAngle]. Same as shear modulus. |
| Mobility, ionic |
kg-1.m-1.s2.A |
m2.s-1.V-1 |
[Velocity]/[Electric field strength] . |
| Molality |
kg-1.mol |
mol/kg |
[Quantity]/[Mass]. A way to specify concentration of a solution. |
| Molar charge |
s.A.mol-1 |
C.mol-1 |
[Charge]/[Quantity] |
| Molar concentration |
m-3.mol |
|
[Quantity]/[Volume]. Same as concentration |
| Molar conductivity, electric |
kg-1.m-3.s3.A2.mol-1 |
S.m-1.mol-1 |
[El.conductivity]/[Concentration]. |
| Molar density |
m-3.mol |
|
[Quantity]/[Volume]. Same as concentration. |
| Molar energy |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Energy]/[Quantity]. |
| Molar enthalpy |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Enthalpy]/[Quantity]. Like molar heat. |
| Molar entropy |
kg.m2.s-2.K-1.mol-1 |
J.K-1.mol-1 |
[Entropy]/[Quantity]. |
| Molar free energy |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Free energy]/[Quantity]. Also molar Helmholtz function |
| Molar free enthalpy |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Free enthalpy]/[Quantity]. Also molar Gibbs function |
| Molar heat |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Heat]/[Quantity]. |
| Molar heat capacity |
kg.m2.s-2.K-1.mol-1 |
J.K-1.mol-1 |
[Heat capacity]/[Quantity]. |
| Molar internal energy |
kg.m2.s-2.mol-1 |
J.mol-1 |
[Internal energy]/[Quantity]. Like molar heat. |
| Molar mass |
kg.mol-1 |
|
[Mass]/[Quantity] |
| Molar production rate |
mol.s-1 |
katal |
[ΔQuantity]/[Time]. Like katalytic activity. |
| Molar refractivity |
m3.mol-1 |
|
[(r2-1)/(r2+2)]/[Concentration], where r is the refractive index |
| Molar relaxivity |
m3.s-1.mol-1 |
|
[Relaxation rate]/[Concentration]. |
| Molar solubility |
m-3.mol |
|
[Quantity]/[Volume]. Same as concentration |
| Molar volume |
m3.mol-1 |
|
[Volume]/[Quantity]. |
| Molarity |
m-3.mol |
|
[Quantity]/[Volume]. Same as concentration or molar density |
| Molecular quantum charge |
1 |
Dimensionless |
[Charge of a molecule]/[Elementary charge quantum] |
| Moment of force |
kg.m2.s-2 |
N.m |
[Force]*[Distance]. |
| Moment of motion |
kg.m.s-1 |
|
[Mass]*[Velocity], [Mass flow]*[Distance]. |
| Mutual inductance |
kg.m2.s-2.A-2 |
V.s.A-1, Wb.A-1, H (henry) |
[ΔPotential]/[dCurrent/dt], [Mag.flux]/[Current] |
| N: |
| Notch resistance |
kg.s-2 |
J.m-2 |
[Energy]/[Area] |
| Number density |
m-3 |
|
[Particles]/[Volume]. |
| Number density, molar |
mol-1 |
|
[Particles]/[Mol]. The Avogadro constant. |
| Number of events/instances |
1 |
|
This covers all kinds of enumerations. |
| Number of turns |
1 |
|
Often used in electric engineering. |
| O: |
| Osmotic pressure |
kg.m-1.s-2 |
Pa |
|
| P: |
| Peltier coefficient |
kg.m2.s-3.A-1 |
W.A-1, V |
[Heat flux]/[Current]. |
| Permeability, magnetic |
kg.m.s-2.A-2 |
H.m-1 |
[Mag.flux density]/[Mag.field strength]. |
| Permittivity, electric |
kg-1.m-3.s4.A2 |
F.m-1 |
[El.flux density]/[El.field strength]. |
| Permittivity, relative |
1 |
Dimensionless |
[Permittivity]/[Permittivity of vacuum]. Dielectric constant. |
| Phase angle |
1 |
rad |
φ in exp(i(ωt+φ)) |
| Phase drift rate |
s-1 |
rad.s-1 |
[Phase angle]/[Time]. |
| Pi coefficient, molar |
kg.m-1.s-2.mol-1 |
J.m-3 |
[ΔInternalEnergy]/[ΔVolume]. |
| Piezzoelectric coefficient |
kg.m.s-3.A-1 |
V.m-1 |
[Electric field strength]/([ΔLength]/[Length]). |
| Plane angle |
1 |
rad |
|
| Polarization, electric |
m-2.s.A |
C.m-2 |
[Charge]/[Area]. Like electric flux density. |
| Position vector |
m |
|
in all Euclidean n-dimensional spaces. |
| Potential, electric |
kg.m2.s-3.A-1 |
W.A-1, J.C-1, V (volt) |
[Power]/[Current], [Energy]/[Charge] |
| Power |
kg.m2.s-3 |
J.s-1, W (watt) |
[ΔEnergy]/[ΔTime]. Equivalent to energy flux. |
| Prandtl number |
1 |
Dimensionless |
[Kinematic viscosity]/[Thermal diffusivity]. |
| Propagation loss |
m-1 |
dB/m |
[Ratio]/m. Used for any other quantity. |
| Poynting vector |
kg.s-3 |
W.m-2 |
[El.field strength]/[Mag.field strength]. Like irradiance |
| Pressure |
kg.m-1.s-2 |
N.m-2, Pa (pascal) |
[Force]/[Area]. |
| Probability of an event |
1 |
|
Real number lying in the interval [0,1]. |
| Probability density on ln-scale |
1 |
Np-1 |
[Probability]/[Natural-logarithmic ratio] |
| Q: |
| Quadrupole moment, electric |
m2.s.A |
C.m2 |
[Electric dipole]*[Distance], [Electric charge]*[Distance2] |
| Quadrupole moment, magnetic |
m3.A |
m.J.T-1 |
[Mag.dipole]*[Distance] |
| Quantity of substance |
mol |
mol |
|
| Quantum charge |
1 |
Dimensionless |
[Charge]/[Elementary charge quantum] |
| Quantum charge, molecular or ionic |
1 |
Dimensionless |
[Molecule/ion charge]/[Charge quantum] |
| Quotient of dispersivity |
m-1 |
|
[ΔRefractive index]/[ΔWavelength] |
| R: |
| Radiance |
kg.s-3.sr-1 |
W.m-2.sr-1 |
([Power]/[Area])/[Solid angle]. |
| Radiation dose |
m2.s-2 |
J.kg-1, Gy (gray) |
[Energy]/[Mass]. |
| Radiation dose rate |
m2.s-3 |
Gy.s-1 |
[Absorbed dose]/[Time]. |
| Radioactivity |
s-1 |
Bq (becquerel) |
[Events]/[Time]. |
| Radius of curvature |
m |
|
of a line in plane/space or surface in space |
| Rotational stiffness |
kg.m2.s-2.rad-1 |
N.m.rad-1 |
[Moment of force]/[Angle]. ... of a structure. |
| Ratio of like quantities |
1 |
Dimensionless |
Q1/Q2, with Q1 and Q2 having the same dimension |
| Reactance, capacitive |
kg.m2.s-3.A-2 |
Ω (ohm) |
1/(i[Angular frequency].[Capacitance]) |
| Reciprocal space position |
m-1 |
|
same as k-space vector. |
| Redox potential |
kg.m2.s-3.A-1 |
V (volt) |
Same as reduction potential. |
| Reduction potential |
kg.m2.s-3.A-1 |
V (volt) |
Same as redox potential. |
| Refractive index |
1 |
Dimensionless |
Light speeds ration (in a medium)/(in vacuum). |
| Refractivity, molar |
m3.mol-1 |
|
[(r2-1)/(r2+2)]/[Concentration] |
| Refractivity, specific |
m3.kg-1 |
|
[(r2-1)/(r2+2)]/[Specific density], |
| Relative differential |
1 |
Dimensionless |
dQ/Q, d{ln(Q)}, for any quantity Q. Also log-scale differential |
| Relative evolution rate |
s-1 |
|
d{ln(Q)}/dt = (dQ/dt)/Q. Also evolution rate on log-scale |
| Relative permeability, magnetic |
1 |
Dimensionless |
[Permeability]/[Permeability of vacuum]. |
| Relative permittivity, electric |
1 |
Dimensionless |
[Permittivity]/[Permittivity of vacuum]. Dielectric constant. |
| Relative variation |
1 |
Dimensionless |
ΔQ/Q, for any quantity Q. |
| Relaxation rate |
s-1 |
|
1/[Relaxation time]. Used in all branches of Science. |
| Relaxation time |
s |
|
Used in all branches of Science. |
| Relaxivity, molar |
m3.s-1.mol-1 |
|
[Relaxation rate]/[Concentration]. |
| Reluctance, magnetic |
kg-1.m-1.s2.A2 |
m.H-1 |
1/[Permeability]. |
| Resistance, electric |
kg.m2.s-3.A-2 |
V.A-1, Ω (ohm) |
[ΔPotential]/[Current] |
| Resistance, thermal |
kg-1.m-2.s3K |
K/W |
of a device. [ΔT]/[Power]. |
| Resistance to impact |
kg.s-2 |
J.m-2 |
[Energy]/[Area]. Same dimension as notch resistance |
| Resistivity, electric |
kg.m3.s-3.A-2 |
Ω.m |
([Resistance]*[Length])/[Area]. |
| Reynolds number |
1 |
Dimensionless |
[Velocity]*[length]/[Kinematic viscosity] |
| RF attenuation |
m-1 |
dB/m |
[Ratio]/m. Applies to propagation. |
| S: |
| Seeback coefficient |
kg.m2.s-3.A-1.K-1 |
V.K-1 |
[ΔPotential]/[ΔTemperature]. Same as thermoelectric power |
| Self-diffusion coefficient |
m2.s-1 |
|
[Distance2]/[Time]. |
| Settling rate |
s-1 |
typically dB/s |
[Ratio]/[ΔTime]. |
| Shear modulus |
kg.m.s-2 |
N, N.rad-1 |
[Force]/[ΔAngle]. Same as modulus of rigidity |
| Softening point |
K |
|
Temperature at which hardness drops below a level. |
| Solid angle |
1 |
sr (steradian) |
|
| Solubility, molar |
m-3.mol |
|
[Quantity]/[Volume]. Same as concentration |
| Sonic attenuation |
m-1 |
dB/m |
[Power ratio]/m. Applies to propagation. |
| Specific charge |
kg-1.s.A |
C.kg-1 |
[Charge]/[Mass]. Charge/mass ratio. |
| Specific density |
kg.m-3 |
|
[Mass]/[Volume]. Same as density of mass |
| Specific energy |
m2.s-2 |
J.kg-1 |
[Energy]/[Mass]. |
| Specific enthalpy |
m2.s-2 |
J.kg-1 |
[Enthalpy]/[Mass]. Like specific heat. |
| Specific entropy |
m2.s-2.K-1 |
J.K-1.kg-1 |
[Entropy]/[Mass]. |
| Specific free energy |
m2.s-2 |
J.kg-1 |
[Free energy]/[Mass]. Also specific Helmholtz function |
| Specific free enthalpy |
m2.s-2 |
J.kg-1 |
[Free enthalpy]/[Mass]. Also specific Gibbs function |
| Specific heat |
m2.s-2 |
J.kg-1 |
[Heat]/[Mass]. |
| Specific heat capacity |
m2.s-2.K-1 |
J.K-1.kg-1 |
[Heat capacity]/[Mass]. |
| Specific internal energy |
m2.s-2 |
J.kg-1 |
[Internal energy]/[Mass]. Like specific heat. |
| Specific refractivity |
m3.kg-1 |
|
[(r2-1)/(r2+2)]/[Specific density] |
| Specific volume |
m3.kg-1 |
|
[Volume]/[Mass]. |
| Speed |
m.s-1 |
|
[Distance]/[Time]. Same as velocity. |
| Spin |
1 |
Dimensionless |
of a quantum particle |
| Star magnitude |
1 |
Dimensionless |
m-m' = -100.4(S/S'), where S,S' are luminous fluxes of two stars |
| Stiffness, linear |
kg.s-2 |
N.m-1 |
[Force]/[Displacement]. ... of a structure. |
| Stiffness, rotational |
kg.m2.s-2.rad-1 |
N.m.rad-1 |
[Moment of force]/[Angle]. ... of a structure. |
| Strain point |
K |
|
Temperature at which viscosity drops below 1013.5 Pa.s |
| Strength, compressive |
kg.m-1.s-2 |
N.m-2, Pa |
[Force]/[Area]. Same dimension as pressure. |
| Strength, dielectric |
kg.m.s-3.A-1 |
V.m-1 |
[ΔPotential]/[Distance]. Same as electric strength |
| Strength, electric field |
kg.m.s-3.A-1 |
V.m-1 |
[ΔPotential]/[Distance]. Also called electric intensity |
| Strength, ionic |
m-3.mol |
|
Sum([Concentration]*[Ionic quantum charge]2). |
| Strength, magnetic field |
m-1.A |
|
[Current]/[Distance]. Also called magnetic intensity |
| Strength, tensile |
kg.m-1.s-2 |
N.m-2, Pa |
[Force]/[Area]. Same as pressure. |
| Surface density of charge |
m-2.s.A |
C.m-2 |
[Charge]/[Area] |
| Surface element |
m2 |
|
[Distance]*[Distance]. Same as area |
| Surface energy |
kg.s-2 |
J/m2 |
[Energy]/[Area]. Same as surface tension. |
| Surface tension |
kg.s-2 |
N/m |
[Force]/[Length]. Same as surface energy. |
| Susceptance, capacitive |
kg-1.m-2.s3.A2 |
S (siemens) |
1/[Reactance]. |
| Susceptibility, magnetic |
1 |
Dimensionless |
[Relative permeability]-1. |
| Stress |
kg.m-1.s-2 |
Pa, N.m-2 |
[Force]/[Area]. Same as pressure. |
| T: |
| Temperature |
K |
K (kelvin) |
|
| Temperature gradient |
K.m-1 |
|
[ΔTemperature]/[Distance]. Same as thermal gradient |
| Tensile strength |
kg.m-1.s-2 |
N.m-2, Pa |
[Force]/[Area]. Same as pressure. |
| Tension |
kg.m-1.s-2 |
Pa, N.m-2 |
[Force]/[Area]. Like pressure. |
| Thermal conductivity |
kg.m.s-3.K-1 |
W.m-1.K-1 |
[Heat flux]/([Distance]*[ΔTemperature]). Same as heat conductivity |
| Thermal diffusivity |
m2.s-1 |
|
([∂Temperatute]/[∂Time])/[∇2Temperature]. |
| Thermal expansion coefficient |
K-1 |
|
([ΔLength]/[Length])/[Temperature]. |
| Thermal gradient |
K.m-1 |
|
[ΔTemperature]/[Distance]. Same as temperature gradient |
| Thermal resistance |
kg-1.m-2.s3K |
K/W |
of a device. [ΔT]/[Power]. |
| Thermodynamic force |
kg.m.s-2.mol-1 |
N/mol |
[ΔChemical potential]/[Distance]. |
| Thermoelectric power | Thermopower |
kg.m2.s-3.A-1.K-1 |
V.K-1 |
[ΔPotential]/[ΔTemperature]. Same as Seeback coefficient |
| Thomson coefficient |
kg.m2.s-3.A-1.K-1 |
W.K-1.A-1 |
[Heat flux]/([ΔTemperature]*[Current]). |
| Time |
s |
s (second) |
|
| Torque |
kg.m2.s-2 |
N.m |
[Force]*[Distance]. Same as moment of force |
| Traction |
kg.m.s-2 |
N (newton) |
Maximum tangential force before slipping. |
| Traction coefficient |
1 |
Dimensionless |
[Traction]/[Weight]. |
| Transmission loss |
m-1 |
dB/m |
[Ratio]/m. Used for any other quantity. |
| U: |
| V: |
| van der Waals constant: a |
kg.m5.s-2 |
Pa.m6 |
a in (p+a/V2)(V-b)=RT. |
| van der Waals constant: b |
m3 |
|
b in (p+a/V2)(V-b)=RT. |
| van der Waals virial constant: A |
kg-1.m5.s-2.mol-2 |
|
A in p=(n/V)RT+(n/V)2(RTB-A). |
| van der Waals virial constant: B |
kg-1.m3.mol-1 |
|
B in p=(n/V)RT+(n/V)2(RTB-A). |
| Variance of current noise nJ2 |
s.A2 |
A2/Hz |
[Current]2/[Bandwidth] |
| Variance of voltage noise nV2 |
kg2.m4.s-5.A-2 |
V2/Hz |
[Voltage]2/[Bandwidth] |
| Vector potential, electromagnetic |
kg.m.s-2.A-1 |
V.s.m-1, T.m |
[El.field strength]*[Time], [Mag.flux density]*[Distance] |
| Velocity |
m.s-1 |
|
[Distance]/[Time]. Same as speed. |
| Verdet constant |
kg-1.m-1.s2.A1 |
rad.m-1.T-1 |
([Angle]/[Length])/[Magnetic flux density] |
| Virial coefficient: second |
kg.m5.s-2.mol-2 |
Pa.(mol.m-3)-2 |
A in p=(n/V)RT+A(n/V)2+B(n/V)3+C(n/V)4. |
| Virial coefficient: third |
kg.m8.s-2.mol-3 |
Pa.(mol.m-3)-3 |
B in p=(n/V)RT+A(n/V)2+B(n/V)3+C(n/V)4. |
| Virial coefficient: fourth |
kg.m11.s-2.mol-4 |
Pa.(mol.m-3)-4 |
C in p=(n/V)RT+A(n/V)2+B(n/V)3+C(n/V)4. |
| Viscosity, dynamic |
kg.m-1.s-1 |
Pa.s |
([Force]/[Area])/[ΔVelocity] |
| Viscosity, kinematic |
m2.s-1 |
|
[Dynamic viscosity]/[Density] |
| Voltage |
kg.m2.s-3.A-1 |
V |
[ΔPotential], same as electromotive force |
| Voltage noise, variance nV2 |
kg2.m4.s-5.A-2 |
V2/Hz |
[Voltage]2/[Bandwidth] |
| Volume |
m3 |
|
[Area]*[Distance] |
| Volume concentration |
1 |
Dimensionless |
[Volume of substance]/[Total volume] |
| W: |
| Wavelength |
m |
|
[Wave velocity]/[Frequency]. |
| Wavenumber |
m-1 |
|
[Number of waves]/[Distance]. |
| Work function |
kg.m2.s-2 |
J, eV |
[Energy] needed to remove an electron. |
| X: |
| Y: |
| Young modulus |
kg.m-1.s-2 |
N.m-2, Pa |
[Stress]/([ΔLength]/[Length]). |
| Z: |
