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Re: POLARIZATION



At 11:06 6/16/98 -0800, John Mallinckrodt wrote:
On Tue, 16 Jun 1998, brian whatcott wrote:

" Here's a weak, quantum argument:
"
" A linear wave has twice the amplitude of its two component helical waves.
" A helical wave has the same amplitude as its component linear waves.
" In the limit, smaller helical waves are permitted than linear waves. QED

Setting aside the question of whether or not there is any quantum
mechanical sense to be made of the above (which Leigh has already
addressed), I'd simply point out that the proposition itself is
at best misleading.

The *rms* amplitude (i.e., the only one that "really matters") of
a transverse wave is always sqrt(2) times larger than that of its
two equal amplitude component waves whether the wave is linear and
the components helical or vice-versa. This is a simple
mathematical result and it (reassuringly) agrees with the dictum
of conservation of energy since the intensity of a wave is
proportional to the mean square amplitude.

John

It is certainly not difficult to frame an elementary rebuttal to
this curious post.
If John admits the possibility of superposing waves of linear
polarization, then let him consider two waves of equal amplitude
(rms or any other measure!) which are pi radians different in phase
but otherwise identical.
The simple result is cancellation.
(Or at least this is my conclusion. Would John say it is in error?)


Brian Whatcott Altus OK