Superposition
Cecil Moore wrote:
Cecil Moore wrote:
Gene Fuller wrote:
Sorry. I missed it because it is not there. They don't say any such
thing.
Yes they do - I distinctly remember reading it.
I will prove it to you as soon as I find my book.
I'm pretty sure it is in the section which discusses
the irradiance (power density) equation. It says the
total irradiance of two waves of the same magnitude
that are interfering can be up to four times the
irradiance of one wave.
Cecil,
The physical effect is well known and is non-controversial, even on
RRAA. What is at issue is all of the philosophical gibberish that seems
to surround the reality.
The exact words from B&W on page 289 of the 7th edition:
"the intensity varies between a maximum value Imax = 4I1, and a minimum
value Imin = 0"
In the 6th edition the same words are on page 259.
The modern convention is to use "irradiance" instead of "intensity",
since "intensity" can have multiple meanings.
What B&W *don't* say is anything about two 1 watt waves interacting,
waves exhibiting constructive and destructive interference, cause and
effects relationships, or even energy conservation.
All of those are things written by more casual writers, such as Hecht,
Melles-Griot, and the FSU Java dudes. There is nothing wrong with that
type of explanation for simple illustration, but it runs out of gas when
trying to support detailed analysis. One quickly ends up with silliness
such as waves that are launched and then cancel destructively within a
short (but undefined) distance. None of that nonsense occurs if one
simply applies the standard analysis techniques such as used by B&W.
73,
Gene
W4SZ
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