this is only true for hot body.. for gas emission lights (fluorescent) that is not
true.
http://users.megapathdsl.net/~solo/w...m_physics.html
Ingrid

It refers to the temperature a black body would have to be to create
that light.
You know red hot, white hot etc, that is the thing. If you could heat a
piece of steel to 5000 degrees K it would look like daylight, instead of
just red hot.