| Quantity |
Unit Name |
Unit
Symbol |
Unit
Definition |
| Length
|
meter
|
m
|
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 mass of the international prototype of the kilogram (the standard body preserved at Sèvres, France).
|
| Time
|
second
|
s
|
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 133Cs atom.
|
| Electric current
|
ampere
|
A
|
The constant current which, if maintained in two straight parallel conductors of infinite length, of
negligible circular cross section, and placed 1 m apart in vacuum, would produce between these
conductors a force equal to 200 nN per meter of length.
|
| Thermodynamic Temperature
|
kelvin
|
K
|
The fraction 1/273.16 of the thermodynamic temperature of the triple point of water.
|
| Luminous Intensity
|
candela
|
cd
|
The candela is the luminous intensity, in a given direction, of a source that
emits monochromatic radiation of frequency 540 THz and that has
a radiant intensity in that direction of 1/683 watt per steradian.
|
| Amount of substance
|
mole
|
mol
|
The amount of substance of a system which contains as many elementary entities
as there are atoms in 0.012 kg of carbon 12.
See notes
|
