Variables commonly used in physics

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Symbol Meaning SI Unit of Measure
\mathbf{E} electric field volt per meter
\mathbf{H} magnetic field strength ampere per meter
\mathbf{D} electric displacement field coulomb per square meter
\mathbf{B} magnetic flux density
also called the magnetic induction.
tesla, or equivalently,
weber per square meter
\ \rho \ free electric charge density,
not including dipole charges bound in a material
coulomb per cubic meter
\mathbf{J} free current density,
not including polarization or magnetization currents bound in a material
ampere per square meter
d\mathbf{A} differential vector element of surface area A, with infinitesimally

small magnitude and direction normal to surface S

square meters
dV \ differential element of volume V enclosed by surface S cubic meters
d \mathbf{l} differential vector element of path length tangential to contour C enclosing surface S meters
\nabla \cdot the divergence operator per meter
\nabla \times the curl operator per meter
\mathbf{F} force newtons
\mathbf{p} momentum kilogram-meters per second
t time seconds
q electric charge coulombs
\mathbf{v} velocity meters per second
ω angluar frequency or angular speed radians per second
T periodicity seconds
f frequency hertz
v tangential velocity of a point about the axis of rotation meters per second
r radius of rotation or distance between two masses meters
G the gravitational constant newton meters squared per kilogram squared
m mass kilograms
a acceleration meters per second squared
Λ cosmological constant 1 / seconds squared
λ wavelength meter
τ torque newton meters
\mathbf{\mu} magnetic moment ampere square meters
d impact parameter
d distance meters
e eccentricity
Planck's constant joule seconds
The reduced Planck's constant joule seconds
i intensity; Cartesian x-axis basis unit vector
j Cartesian y-axis basis unit vector
k Boltzmann constant; Cartesian z-axis basis unit vector joules per kelvin
n refraction index; principal quantum number
p pressure pascals
q charge
s arc length
u four-velocity; relativistic mass; energy density
H Hamiltonian; magnetic field strength
I action; intensity; electric current amperes
J current density amperes per square meter
K kinetic energy joules
L inductance; luminosity henries; candelas per square metre
M magnetization; moment
N normal vector; atomic number
P power watts
Q Electric Charge coulombs
R Electrical resistance; Ricci tensor; radiancy ohms
T Thermodynamic Temperature kelvins
U potential energy joules
V voltage volts
α angular acceleration; fine structure constant
β velocity in terms of c 299,792,458 meters per second
γ Lorentz factor
ε electric constant farads per meter
η efficiency or viscosity
Θ angular displacement radians
Κ torsion constant newton meters per radian
ν frequency hertz
ρ density kilograms per cubic meter
Φ field strength
Ψ wavefunction

[edit] See also