Symbol
|
Meaning
|
SI unit of measure
|
|
magnetic vector potential
|
tesla meter (T⋅m)
|
|
area
|
square meters (m2)
|
amplitude
|
meter
|
atomic mass number
|
unitless
|
|
acceleration
|
meters per second squared (m/s2)
|
|
magnetic flux density also called the magnetic field density or magnetic induction
|
tesla (T), or equivalently, weber per 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
|
meters 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
|
coulomb per square meter (C/m2)
|
|
density
|
kilograms per cubic meter (kg/m3)
|
diameter
|
meter (m)
|
|
distance
|
meter (m)
|
direction
|
unitless
|
impact parameter
|
meter (m)
|
differential (e.g. )
|
varied depending on context
|
|
differential vector element of surface area A, with infinitesimally small magnitude and direction normal to surface S
|
square meter (m2)
|
|
differential element of volume V enclosed by surface S
|
cubic meter (m3)
|
|
electric field
|
newton per coulomb (N⋅C−1), or equivalently, volt per 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
|
newton meter squared per kilogram squared (N⋅m2/kg2)
|
shear modulus
|
pascal (Pa) or newton per square meter (N/m2)
|
|
acceleration due to gravity
|
meters per second squared (m/s2), or equivalently, newtons per kilogram (N/kg)
|
|
magnetic field strength
|
ampere per 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
|
watt per square meter (W/m2)
|
sound intensity
|
watt per square meter (W/m2)
|
electric current
|
ampere (A)
|
moment of inertia
|
kilogram 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
|
kilogram meter per second (kg⋅m/s)
|
|
jerk
|
meters per second cubed (m/s3)
|
|
imaginary unit (electrical)
|
unitless
|
|
Cartesian y-axis basis unit vector
|
unitless
|
|
kinetic energy
|
joule (J)
|
|
wave vector
|
radians per meter (m−1)
|
|
Boltzmann constant
|
joule per kelvin (J/K)
|
wavenumber
|
radians per meter (m−1)
|
stiffness
|
newtons 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)
|
|
length
|
meter (m)
|
ℓ
|
azimuthal quantum number
|
unitless
|
|
magnetization
|
amperes per meter (A/m)
|
|
moment of force often simply called moment or torque
|
newton 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
|
kilogram 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
|
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
|
joule per 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)
|