On Fri, 29 Jul 2005 16:58:29 -0700, Jim Kelley
wrote:
It is quite evident that through the actions of the first interface,
that there is less energy incident upon the second interface.
Further, given that both interfaces operate with identical reflective
and transmissive properties, it follows the second interface could not
reflect enough to totally negate the reflections of the first.

True for any one reflection.

Hi Jim,

And true for ALL accumulated reflections there after. Reflections do
not add any energy to the cup when the first interface is draining it
more quickly.

But as an optical engineer I'm sure you're
aware that, even in a lossy medium, a given wave reflects back and forth
multiple times before it's amplitude is reduced to insignificance. As
you know, the measured amplitude at a surface would then be the
superposition of multiple successively reflected waves.

My analysis allowed ALL of the energy in the reflection from the
second interface ( 0.098X) to combine with the first reflection
(0.11X). This total superposition was both more than generous, and at
the same time very unlikely; and yet with this generous allowance
there is still excess reflection from the first interface. Hence for
something less than total superposition of ALL energies, it hardly
bodes a better yield in total cancellation - the energy just isn't
there in the first place. 0.098X 0.11X is the simple economics of
the balance.

As an optical engineer, I've dealt with the harsh reality of this myth
of total reflection cancellation. I've designed systems with 9 orders
of dynamic range and the couple of percent dashed off as being
invisible by academics was distinctly and overwhelmingly present.
Basically I had the advantage in fluorescence measurement in being
able to turn off my detector during the initial flash to suppress the
reflection products in time rather than in these shenanigans (I did
them too - and certainly much more - because even the detector can be
blinded in its "off" state).

Basically these claims are for first year students where demanding too
much inquiry would push them into switching majors to Business school.
Simple optics with simple, ordinary glasses exhibit quite useful
results, but they do not embody a proof. To anyone following the math
of my presentation, it is quite obvious what WOULD tend towards a more
complete cancellation - and such a subtle shift in the formula
diverges only slightly from the choir book hymn. It's not that hard
when the interface ratios drive the answer.

73's
Richard Clark, KB7QHC