Electro-Magnetic Units
SI Base Units for electricity & magnetism: meter (m), kilogram (kg), second (s) and ampere (A)
Electro-Magnetic Quantities of Interest
Quantity
Commonly used
Variable
Q, q
F
Unit Name
Electric Field
E
(none)
Electric Flux
E
(none)
V, V, E
Volt
V
Capacitance
C
Farad
F
Current
I, i
Ampere
A
A
Resistance
R
Ohm

Magnetic Field
B
Tesla
T
Magnetic Flux
B
Weber
Wb
Inductance
L
Henry
H
Energy
U, E
Joule
J
Power
P, P
Watt
W
kg·m2
A 2 ·s3
kg
A·s2
kg·m2
A·s2
kg·m2
A 2 ·s2
kg·m2
s2
kg·m2
s3
Charge
Force
Electric Potential, EMF
Coulomb
Newton
Unit
Symbol
C
N
In Terms of SI
Base Units
A·s
kg·m
s2
kg·m
A·s3
kg·m3
A·s3
kg·m2
A·s3
A2  s 4
kg·m2
In Terms of Other
Common Units
V·F, J/V
C·V, C·m·T/s
N/C, V/m
V·m, N·m2/C
A·, H·A/s, C/F, Wb/s, J/C
C/V
C/s, V/
V/A
Wb/m2, V·s/m2
V·s , T·m2
Wb/A, V·s/A, T·m2/A
N·m, C2/F, H·A2, F·V2, C·V
J/s, N·m/s, A·V, A2·
Definitions of SI Units
Quantity
Length
Definition
The meter is the length of the path travelled by light in vacuum during a
time interval of 1/299,792,458 of a second.
Mass
kilogram
kg
The kilogram is the unit of mass; it is equal to the mass of the
international prototype of the kilogram.
Time
second
s
The second is the duration of 9,192,631,770 periods of the radiation
corresponding to the transition between the two hyperfine levels of the
ground state of the cesium 133 atom.
Electric current
ampere
A
The ampere is that constant current which, if maintained in two straight
parallel conductors of infinite length, of negligible circular crosssection,
and placed 1 meter apart in vacuum, would produce between
-7
these conductors a force equal to 2 × 10 newton per meter of length.
Temperature
kelvin
K
The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16
of the thermodynamic temperature of the triple point of water.
Amount
mole
mol
The mole is the amount of substance of a system which contains as many
elementary entities as there are atoms in 0.012 kilogram of carbon 12; its
symbol is “mol.”
Light intensity
candela
cd
The candela is the luminous intensity, in a given direction, of a source
12
that emits monochromatic radiation of frequency 540 × 10 hertz and
that has a radiant intensity in that direction of 1/683 watt per steradian.
Ref: ‘The International System of Units’, NIST Special Publication 330, 2008 ed., Taylor, Barry N. and Thompson, Ambler.
R. Gist
Unit
meter
Symbol
m
2/5/2010