View source for Physics Study Guide/Greek alphabet

{{PSG}}

=About the ''Common uses in Physics''=
While these are indeed common usages, it should be pointed out that there are many other usages and that other letters are used for the same purpose. The reason is quite simple: there are only so many symbols in the Greek and Latin alphabets, and scientists and mathematicians generally do not use symbols from other languages. It is a common trap to associate a symbol exclusively with some particular meaning, rather than learning and understanding the physics and relations behind it.


{| style="text-align:center" cellpadding="5" cellspacing="0" border="1"
|+'''Greek Alphabet'''
!Capital !! Lower case !! Name !! Common use in Physics
|-
| {{math|size=1.5em|<math>\Alpha</math>}} || {{math|size=1.5em|<math>\alpha</math>}} || alpha
|align=left| Angular acceleration<br/>Linear expansion<br/>Coefficient<br/>Alpha particle (helium nucleus)<br/>Fine Structure Constant
|-
| {{math|size=1.5em|<math>\Beta</math>}} || {{math|size=1.5em|<math>\beta</math>}} || beta
|align=left| Beta particle &mdash; high energy electron<br/>Sound intensity
|-
| {{math|size=1.5em|<math>\Gamma</math>}} || {{math|size=1.5em|<math>\gamma</math>}} || gamma
|align=left| Gamma ray (high energy EM wave)<br>Ratio of heat capacities (in an ideal gas)<br>Relativistic correction factor
Shear strain
|-
| {{math|size=1.5em|<math>\Delta</math>}} || {{math|size=1.5em|<math>\delta</math>}} || delta
|align=left| &Delta;="Change in" <br> &delta;="Infinitesimal change in (), also used to denote the Dirac delta function (reference needed)"
|-
| {{math|size=1.5em|<math>\Epsilon</math>}} || {{math|size=1.5em|<math>\epsilon</math>}} || epsilon
|align=left| Emissivity<br>Strain (Direct e.g. tensile or compression)<br>Permittivity<br>EMF
|-
| {{math|size=1.5em|<math>\Zeta</math>}} || {{math|size=1.5em|<math>\zeta</math>}} || zeta
|align=left| (no common use)
|-
| {{math|size=1.5em|<math>\Eta</math>}} || {{math|size=1.5em|<math>\eta</math>}} || eta
|align=left| Viscosity<br>Energy efficiency
|-
| {{math|size=1.5em|<math>\Theta</math>}} || {{math|size=1.5em|<math>\theta</math>}} || theta
|align=left| Angle (&deg;, rad)<br>Temperature
|-
| {{math|size=1.5em|<math>\Iota</math>}} || {{math|size=1.5em|<math>\iota</math>}} || iota
|align=left| The lower case <math>\iota\;</math> is rarely used, while <math>\Iota</math> is sometimes used for the identity matrix or the moment of inertia. Note that <math>\iota</math> is not to be confused with the Roman character <math>i</math> (which has a dot and is much more widely used in mathematics and physics).
|-
| {{math|size=1.5em|<math>\Kappa</math>}} || {{math|size=1.5em|<math>\kappa</math>}} || kappa
|align=left| Spring constant<br>Dielectric constant
|-
| {{math|size=1.5em|<math>\Lambda</math>}} || {{math|size=1.5em|<math>\lambda</math>}} || lambda
|align=left| Wavelength<br>Thermal conductivity<br>Constant<br>Eigenvalue of a matrix<br>Linear density
|-
| {{math|size=1.5em|<math>\Mu</math>}} || {{math|size=1.5em|<math>\mu</math>}} || mu
|align=left| Coefficient of friction<br>Electrical mobility<br>Reduced mass<br>Permeability
|-
| {{math|size=1.5em|<math>\Nu</math>}} || {{math|size=1.5em|<math>\nu</math>}} || nu
|align=left| Frequency
|-
| {{math|size=1.5em|<math>\Xi</math>}} || {{math|size=1.5em|<math>\xi</math>}} || xi
|align=left| Damping cofficient
|-
| {{math|size=1.5em|<math>\Omicron</math>}} || {{math|size=1.5em|<math>\omicron</math>}} || omicron
|align=left| (no common use)
|-
| {{math|size=1.5em|<math>\Pi</math>}} || {{math|size=1.5em|<math>\pi</math>}} || pi
|align=left| Product symbol <math>\Pi</math><br> Circle number <math>\pi:=3.14159...</math>
|-
| {{math|size=1.5em|<math>\Rho</math>}} || {{math|size=1.5em|<math>\rho</math>}} || rho
|align=left| Volume density<br> Resistivity
|-
| {{math|size=1.5em|<math>\Sigma</math>}} || {{math|size=1.5em|<math>\sigma</math>}} || sigma
|align=left| Sum symbol<br>Boltzmann constant<br>Electrical conductivity<br>Uncertainty<br>Stress (Direct e.g. tensile, compression)<br>Surface density
|-
| {{math|size=1.5em|<math>\Tau</math>}} || {{math|size=1.5em|<math>\tau</math>}} || tau
|align=left| Torque<br>Tau particle (a lepton)<br>Time constant
Shear stress
|-
| {{math|size=1.5em|<math>\Upsilon</math>}} || {{math|size=1.5em|<math>\upsilon</math>}} || upsilon
|align=left| mass to light ratio
|-
| {{math|size=1.5em|<math>\Phi</math>}} || {{math|size=1.5em|<math>\phi</math>}} || phi
|align=left| Magnetic/electric flux<br>Angle (&deg;, rad)
|-
| {{math|size=1.5em|<math>\Chi</math>}} || {{math|size=1.5em|<math>\chi</math>}} || chi
|align=left| Rabi frequency (lasers)<br>Susceptibility<br>Mole Fraction
|-
| {{math|size=1.5em|<math>\Psi</math>}} || {{math|size=1.5em|<math>\psi</math>}} || psi
|align=left| Wave function
|-
| {{math|size=1.5em|<math>\Omega</math>}} || {{math|size=1.5em|<math>\omega</math>}} || omega
|align=left| Ohms (unit of electrical resistance)<br>&omega; Angular velocity
|}

=See Also=
[[w:Greek alphabet|Greek alphabet]] on [[w:Main Page|Wikipedia]]

[[wikipedia:Greek_letters_used_in_mathematics,_science,_and_engineering|Greek letters used in mathematics, science, and engineering]]
{{BookCat}}