Physics Study Guide/Greek alphabet

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Physics Study Guide (Print Version)
Units Linear Motion Force Momentum Normal Force and Friction Work Energy
Torque & Circular Motion Fluids Fields Gravity Waves Wave overtones Standing Waves Sound
Thermodynamics Electricity Magnetism Optics
Physical Constants Frictional Coefficients Greek Alphabet Logarithms Vectors and Scalars Other Topics

About the Common uses in Physics[edit]

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.

Greek Alphabet
Capital Lower case Name Common use in Physics
alpha Angular acceleration
Linear expansion
Alpha particle (helium nucleus)
Fine Structure Constant
beta Beta particle — high energy electron
Sound intensity
gamma Gamma ray (high energy EM wave)
Ratio of heat capacities (in an ideal gas)
Relativistic correction factor

Shear strain

delta Δ="Change in"
δ="Infinitesimal change in"
epsilon Emissivity
Strain (Direct e.g. tensile or compression)
zeta (no common use)
eta Viscosity
Energy efficiency
theta Angle (°, rad)
iota The lower case is rarely used, while is sometimes used for the identity matrix or the moment of inertia. Note that is not to be confused with the Roman character (which has a dot and is much more widely used in mathematics and physics).
kappa Spring constant
Dielectric constant
lambda Wavelength
Thermal conductivity
Eigenvalue of a matrix
Linear density
mu Coefficient of friction
Electrical mobility
Reduced mass
nu Frequency
xi Damping cofficient
omicron (no common use)
pi Product symbol
Circle number
rho Volume density
sigma Sum symbol
Boltzmann constant
Electrical conductivity
Stress (Direct e.g. tensile, compression)
Surface density
tau Torque
Tau particle (a lepton)
Time constant

Shear stress

upsilon mass to light ratio
phi Magnetic/electric flux
Angle (°, rad)
chi Rabi frequency (lasers)
psi Wave function
omega Ohms (unit of electrical resistance)
ω Angular velocity

See Also[edit]

Greek alphabet on the Wikipedia missionaries of the sacred heart