Is the distance between a trough and crest one wavelength?

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SUMMARY

The distance between a trough and a crest in a wave is defined as half a wavelength, while the full wavelength is measured from trough to trough or crest to crest. This distinction is crucial, especially when discussing pure sine waves versus complex waves, which can contain multiple local crests and troughs within a single wavelength. Understanding this concept is essential for accurately analyzing wave behavior in various contexts.

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TheShapeOfTime
Is the distance between a trough and crest one wavelength?
 
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No, 1 wavelength is trough to trough or peak to peak.
 
Last edited:
TheShapeOfTime said:
Is the distance between a trough and crest one wavelength?
It seems that you're thinking about a pure sine wave, in which case the wavelength is the distance between crests (or troughs). But waves are not sine waves in general. If its a complex wave (as many waves in the real world are) then there may be many local crests (or troughs) within one wavelength.

Pete
 
Last edited:
TheShapeOfTime said:
Is the distance between a trough and crest one wavelength?

That would be a HALF wavelength!
 
Yeah I was thinking the samething when I first read it. Its the distance beteen two consecutive crest or troughs.
 
Tide said:
That would be a HALF wavelength!

I was thinking this too, but I wasn't sure if a point at the top of a crest was considered in phase with one at the bottom of a trough.

pmb_phy said:
It seems that you're thinking about a pure sine wave, in which case that is correct. But waves are not sine waves in general. If its a complex wave (as many waves in the real world are) then there may be many local crests and troughs within one wavelength.

I've only just been introduced to waves so I have no idea what sine or complex waves are. :redface:
 
Tide said:
That would be a HALF wavelength!
Oy vey! Yes. True. How did I miss that?
TheShapeOfTime said:
I've only just been introduced to waves so I have no idea what sine or complex waves are.
Take a look at this web site. It'll give you an idea.

http://www.udel.edu/idsardi/sinewave/sinewave.html

Uncheck "red" and "sum" and the result is a sine wave. Now check "red" and it will plot another sine wave on the same axis. Now check "sum" and you'll see the function which is the sum of the two which is a wave, but not a sine wave. Uncheck "blue" and "sum" and you'll see only the sum (the "complex"/"non-simple" wave). See the problem of speaking about troughs and crests?

Note: By "complex" I don't mean anything to do with complex numbers. I mean "not a simple sine wave."

Pete
 

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