List of common physics notations
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This is a list of common physical constants and variables, and their notations. Note that bold text indicates that the quantity is a
vector
.
Latin characters
Symbol | Meaning | SI unit of measure |
---|---|---|
magnetic vector potential | meter (T⋅m)
| |
area | square meter (m2)
| |
amplitude | meter
| |
atomic mass number
|
unitless | |
acceleration | meter per second squared (m/s2)
| |
magnetic flux density also called the magnetic field density or magnetic induction |
square meter (Wb/m2)
| |
capacitance | farad (F) | |
heat capacity | joule per kelvin (J⋅K−1) | |
constant of integration | varied depending on context | |
speed of light (in vacuum) | 299,792,458 meters per second (m/s)
| |
speed of sound | meter per second (m/s)
| |
specific heat capacity | joule per kilogram per kelvin (J⋅kg−1⋅K−1) | |
viscous damping coefficient | kilogram per second (kg/s) | |
electric displacement field also called the electric flux density |
square meter (C/m2)
| |
density | cubic meter (kg/m3)
| |
diameter | meter (m)
| |
distance | meter (m)
| |
direction
|
unitless | |
impact parameter | meter (m)
| |
differential (e.g. )
|
varied depending on context | |
normal to surface S
|
square meter (m2)
| |
differential element of volume V enclosed by surface S | cubic meter (m3)
| |
electric field | meter (V⋅m−1)
| |
energy | joule (J) | |
Young's modulus | pascal (Pa) or newton per square meter (N/m2) | |
eccentricity
|
unitless | |
2.71828... (base of the natural logarithm) | unitless | |
electron | unitless | |
elementary charge | coulomb (C) | |
force | newton (N) | |
Faraday constant | coulombs per mole (C⋅mol−1) | |
frequency | hertz (Hz) | |
function | ||
friction | newton (N) | |
electrical conductance | siemens (S) | |
universal gravitational constant | meter squared per kilogram squared (N⋅m2/kg2)
| |
shear modulus | pascal (Pa) or newton per square meter (N/m2) | |
acceleration due to gravity | (N/kg) | |
magnetic field strength | meter (A/m)
| |
Hamiltonian | joule (J) | |
enthalpy | joule (J) | |
thermal current
|
watt (W) | |
height | meter (m)
| |
Planck constant | joule second (J⋅s) | |
reduced Planck constant
|
joule second (J⋅s) | |
action | joule second (J⋅s) | |
intensity | square meter (W/m2)
| |
sound intensity | watt per square meter (W/m2)
| |
electric current | ampere (A) | |
moment of inertia | meter squared (kg⋅m2)
| |
intensity | watt per square meter (W/m2)
| |
imaginary unit | unitless | |
electric current | ampere (A) | |
Cartesian x-axis basis unit vector | unitless | |
current density | ampere per square meter (A/m2)
| |
impulse | meter per second (kg⋅m/s)
| |
jerk | meter per second cubed (m/s3) | |
imaginary unit (electrical) | unitless | |
Cartesian y-axis basis unit vector | unitless | |
kinetic energy | joule (J) | |
wave vector | meter (m−1)
| |
Boltzmann constant | joule per kelvin (J/K) | |
wavenumber | meter (m−1)
| |
stiffness | newton per meter (N⋅m−1) | |
Cartesian z-axis basis unit vector | unitless | |
angular momentum | newton meter second (N⋅m⋅s or kg⋅m2⋅s−1)
| |
inductance | henry (H) | |
luminosity | watt (W) | |
Lagrangian
|
joule (J) | |
Lagrangian density | joule per cubic meter (J/m3) | |
length | meter (m)
| |
ℓ | azimuthal quantum number | unitless |
magnetization | ampere per meter (A/m)
| |
moment of force often simply called moment or torque |
meter (N⋅m)
| |
mass | kilogram (kg) | |
normal vector | unit varies depending on context | |
atomic number | unitless | |
refractive index | unitless | |
principal quantum number | unitless | |
amount of substance | mole | |
power | watt (W) | |
probability | unitless | |
momentum | meter per second (kg⋅m/s)
| |
pressure | pascal (Pa) | |
electric charge | coulomb (C) | |
heat | joule (J) | |
electric charge | coulomb (C) | |
electrical resistance
|
ohm (Ω) | |
Ricci tensor
|
reciprocal square meter (m−2)
| |
radiancy
|
meter per second
| |
gas constant | joule per mole per kelvin (J⋅mol−1⋅K−1) | |
radius vector (position)
|
meter (m)
| |
radius or distance | meter (m)
| |
surface area | square meter (m2)
| |
entropy | joule per kelvin (J/K) | |
action | joule second (J⋅s) | |
displacement
|
meter (m)
| |
arc length | meter (m)
| |
distance | meter (m)
| |
period
|
second (s) | |
temperature | kelvin (K) or Celsius (C) | |
kinetic energy | joule (J) | |
time | second (s) | |
four-velocity | meter per second (m/s)
| |
potential energy | joule (J) | |
internal energy | joule (J) | |
relativistic mass
|
kilogram (kg) | |
energy density | cubic meter (J/m3)
| |
specific energy | joule per kilogram (J/kg) | |
voltage also called electric potential difference |
volt (V) | |
volume | cubic meter (m3)
| |
shear force | ||
velocity | meter per second (m/s)
| |
weight | newton (N) | |
mechanical work
|
joule (J) | |
width
|
meter (m)
| |
electrical reactance | ohm (Ω) | |
position vector
|
meter (m) | |
displacement
|
meter (m)
| |
a generic unknown | varied depending on context | |
admittance | siemens (S) | |
compressibility factor | unitless | |
electrical impedance | ohm (Ω) | |
impedance of free space | ohm (Ω) |
Greek characters
Symbol | Name | Meaning | SI unit of measure |
---|---|---|---|
alpha
|
alpha particle | ||
angular acceleration | radian per second squared (rad/s2) | ||
fine-structure constant | unitless | ||
beta
|
velocity in terms of the speed of light c | unitless | |
beta particle | |||
gamma | Lorentz factor | unitless | |
photon | |||
gamma ray | |||
shear strain
|
radian | ||
heat capacity ratio | unitless | ||
surface tension | meter (N/m)
| ||
delta | change in a variable (e.g. ) | unitless | |
Laplace operator | per square meter (m−2) | ||
displacement (usually small)
|
meter (m) | ||
Dirac delta function | |||
Kronecker delta (e.g ) | |||
epsilon
|
permittivity | farad per meter (F/m)
| |
strain
|
unitless | ||
epsilon nought | Vacuum permittivity | farad per meter (F/m) | |
zeta | damping ratio
|
unitless | |
eta
|
angular jerk
|
radian per second cubed (rad⋅s−3) | |
energy efficiency | unitless | ||
(dynamic) viscosity (also )
|
pascal second (Pa⋅s) | ||
theta
|
angular displacement | radian (rad) | |
kappa
|
torsion coefficient also called torsion constant |
meter per radian (N⋅m/rad)
| |
lambda | cosmological constant | per second squared (s−2) | |
wavelength | meter (m)
| ||
linear charge density | coulomb per meter (C/m) | ||
eigenvalue
|
non-zero vector | ||
mu | magnetic moment | ampere square meter (A⋅m2)
| |
coefficient of friction
|
unitless | ||
(dynamic) viscosity (also )
|
pascal second (Pa⋅s) | ||
permeability (electromagnetism) | henry per meter (H/m)
| ||
reduced mass | kilogram (kg) | ||
Standard gravitational parameter | cubic meter per second squared | ||
mu nought | Vacuum permeability or the magnetic constant | henry per meter (H/m) | |
nu | frequency | hertz (Hz) | |
kinematic viscosity
|
meter squared per second (m2/s)
| ||
neutrino | |||
xi | electromotive force | volt (V) | |
pi | 3.14159... (irrational number) | unitless | |
rho
|
mass density usually simply called density |
cubic meter (kg/m3)
| |
volume charge density | cubic meter (C/m3)
| ||
resistivity
|
ohm meter (Ω⋅m)
| ||
sigma | summation operator | ||
area charge density | coulomb per square meter (C/m2) | ||
electrical conductivity
|
meter (S/m)
| ||
normal stress
|
pascal (Pa) | ||
scattering cross section | barn (10^-28 m^2) | ||
surface tension | meter (N/m)
| ||
tau | torque | newton meter (N⋅m)
| |
shear stress | pascal (Pa) | ||
time constant | second (s) | ||
6.28318... (2π) | unitless | ||
phi
|
field strength | unit varies depending on context | |
magnetic flux | weber (Wb) | ||
electric potential | volt (V) | ||
Higgs field work function
|
|||
psi
|
wave function | m−3/2 | |
omega | electric resistance | ohm | |
angular frequency | radian per second (rad/s) | ||
angular velocity | radian per second (rad/s) |
Other characters
Symbol | Name | Meaning | SI unit of measure |
---|---|---|---|
nabla dot | the divergence operator often pronounced "del dot" |
per meter (m−1)
| |
nabla cross | the curl operator often pronounced "del cross" |
per meter (m−1)
| |
nabla | delta (differential operator) | ||
"der", "dow", "die", "partial" or simply "d" | partial derivative (e.g. ) | ||
D'Alembert operator | |||
angle brackets
|
average sometimes over Maxwell–Boltzmann distribution |
||
Dirac notation
|
|||
integral | the inverse of the derivative. | unitless |
See also
- List of letters used in mathematics and science
- Glossary of mathematical symbols
- List of mathematical uses of Latin letters
- Greek letters used in mathematics, science, and engineering
- Physical constant
- Physical quantity
- International System of Units
- ISO 31
References
- Elert, Glenn. "Special Symbols". The Physics Hypertextbook. Retrieved 4 August 2021.
- NIST (16 August 2023). "SI Units". www.nist.gov. NIST.