●In SI units & Units of measure:
In
the
International
System
of
Units,
the
base
unit
of
luminous
intensity;
the
luminous
intensity,
in
a
given
direction,
of
a
source
that
emits
monochromatic
radiation
of
frequency
540
×
10¹²
hertz
and
that
has
a
radiant
intensity
in
that
direction
of
1/683
watt
per
steradian.
Symbol:
cd
