On Sep 27, 6:30 pm, "Al" wrote:
Yes, you did. And I agree. Although I think I understand more clearly now
and can rephrase the idea we both agree with so it says this:

given two bulbs that produce the same desired lumen output at one foot from
the bulb, the first bulb being a fist-sized incandescent and the second
being a 4 foot long tube, the difference in the size of the lumen footprint
between the two bulbs is what makes one more desirable than the other. The
first bulb produces a 1 foot by 1 foot space of desired lumens, the second
produces a 1 by 4 foot space of desired lumens.

However, what really through me for a few minutes in what I read he

HOWEVER, from a large or diffuse source such as a fluorescent tube,
the falloff is less drastic because the tube is, in effect, a large
number of overlapping point sources. The handy rule for such a source
is that the intensity falls off as the inverse of the distance, i.e.
twice as far ,1/2 as intense, three times as far, 1/3, etc.

was the difference between "inverse" and "inverse square". One makes the
statement false;

No it doesn't. They refer to completely separate circumstances.


although not so far wrong in the short distances we are
talking about under a bulb, that it was worth jumping to this lovely thread.
The other thing that threw me was the need to state how distance and
intensity are related in the equation. "Twice" and "Three times" mislead
me, ...

I don't see why.

J. Del Col