On Thu, 11 Sep 2008 06:18:14 -0700 (PDT), Art Unwin
wrote:

If I have a flash light that is focussed does this wavelength aproach
still apply?

The reflector (or magnifier lens, take your pick) is on order of at
least 1 centimeter. The light wavelength is on order of 500
nanometers.

Ratio = 20,000:1

Beam is generally no narrower than 15 degrees. At a distance of, say,
6 feet, that beam would cover a diameter of 18 inches. Nothing like a
Lazer (sic) if that is the goal.

73's
Richard Clark, KB7QHC