In message , Andrew Gabriel
writes
BTW, here's a nice experiment you can carry out to observe this effect
in a fluorescent lamp. Take a lamp firmly fixed to a long cord (such as
a car service/inspection lamp), and go out into a large dark area (e.g.
outside at night) where there are no objects for many feet in any
direction. Switch the lamp on, and swing it round and round over your
head on the end of the cord. As it passes in front of you each time,
you will see the stroboscopic effect of the different colour components
which make up the white light, and in particular you will notice how
they are all out of phase with each other, with some of the phosphor
components having much longer persistance than others. Obviously be
careful here -- if you manage to hurl a car inspection lamp through
your neighbour's window, don't come crying to me...

Hmm. I just tried this with a dual lamp 8' fixture and it disintegrated
when I got up to approximately 120rpm. It's made a real mess of the
patio.

--
Asa Rimmer.