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posted to rec.boats
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First recorded activity by BoatBanter: Jan 2008
Posts: 72
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A question about radio, sound, "wave length" etc.
"Eisboch" wrote in message
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"Calif Bill" wrote in message
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"Eisboch" wrote in message
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"Jim" wrote in message
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wrote in message
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On Tue, 15 Jan 2008 17:07:42 -0800 (PST),
wrote:
On Jan 15, 7:50 pm, Tim wrote:
OK, I picked this up on another board,a nd seeing that Eisboch, Tom,
Gene and Larry have had dealings with this stuff. I thought I'd
present it here. It has my curiosity up as well.
I'm not up on physics, concerning this so here goes:
"I searched the web but couldn't find an answer to a simple question
which for my purposes is really a matter of curiosity. Of course,
sometimes these
kinds of questions end up teaching me the most.
Most defintions of wavelength are along the lines of the distance
between points of corresponding phase of two consecutive cycles of a
wave. I'm not
an idiot , so I understand what is a pretty
straightforward definition.
What I don't get is why the term length? I mean, they don't call the
amplitude the waveheight. I kind of think of it as a wavegap. If you
painted a big sine wave on the street and asked me how long it was,
I'd get one
of those little rolling doohickies for measuring and trace the line
through its curve. Without knowing the definition in advance, I
wouldn't think you would
be asking me the straight distance between two points of
corresponding
phase.
I ask this question because I don't understand why it's called what
it's called, not because I want to tell the experts they got it
wrong. It's bugged me for a while, so I've finally decided to take
the
plunge and risk looking stupid.
Thanks in advance for any responses or links to read..."
--
Jim Carr
It is called "length" because it truly is a length.
Wavelength is usually stated as "Peak to Peak", or pp
which is 180 degrees, right? ;-
360 degrees.
Eisboch
Actually is 180 degrees for a peak to peak on a sign wave. But for
frequency, it is point to same point on the next wave. You could measure
it anywhere on the wave. But Positive peak to Positive peak or Negative
peak to Negative Peak or + or - zero crossing all work.
180 degrees positive peak to negative peak or negative peak to next
positive peak.
360 degrees positive peak to positive peak or negative peak to negative
peak, or as you say, any from any point to the next exact point on the
sine wave.
Eisboch
The definition of peak to peak must have changed since I was in A school. I
was taught that positive peak to negative peak or negative peak to positive
peak shal be called peak to peak. (Neener Neener)
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