1987 Ed.]
Metrication
Quantity
Name
Symbol
thermo-
kelvin
K
dynamic
temperature
luminous
candela
cd
intensity
amount of substance
mole
mol
Quantity
Plane angle radian
[CAP. 214
3
Definition
the fraction 1/273.15 of the thermodynamic temperature of the triple point of water.
the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 1012 hertz and has a radiant intensity in that direction of 1/683 of a watt per steradian.
the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12.
Note: When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.
L.N. 189/87.
PART II
The SI supplementary units (See Note (2))
Name
Symbol
rad
→
sr
Definition
the plane angle between two radii of a circle which cut off on the circumference an arc equal in length to the radius.
the solid angle which, having its vertex in the centre of a sphere, cuts off an area of the surface of the sphere equal to that of a square with sides of length equal to the radius of the sphere.
solid angle
steradian
PART III
SI derived units having special names and symbols
(See Notes (3) & (4))
Quantity
Name
Symbol
frequency
hertz
Hz
force
newton
N
Expression in terms of other SI units
1 kg m/s2
pressure stress
pascal
Pa
N/m2
energy, work, quantity of heat
joule
J
N m
power, radiant flux
watt
W
J/s
quantity of electricity,
coulomb
C
A s
electric charge
electric potential,
volt
V
W/A
potential difference.
electromotive force
capacitance
farad
F
C/V