|WikiProject Physics||(Rated Start-class, Mid-importance)|
- 1 Excess
- 2 Simplicity
- 3 image
- 4 Confusing
- 5 Transverse waves travel slower than longitudinal waves ?
- 6 Polarization
- 7 Speed of logitudinal disturbance in transverse waves
- 8 Answer for above question
- 9 Why does this article need cleaned up?
- 10 'Cleaned Up' tag removal
- 11 Removed "No Reference Tag"
- 12 Light wave chart is wrong.
- 13 Ripples in a pond-transverse wave?
- 14 Light Rays
- 15 Experiment's ambiguity
- 16 Misleading Example of Ripples in Intro
Probably an excess of 'longitudinal' material here after the merge. Charles Matthews 21:28, 20 Feb 2004 (UTC)
Some of us just need to know what a transverse wave is. Simple basic information needs to be kept for those of us without a physics degree! — Preceding unsigned comment added by 184.108.40.206 (talk) 16:41, 17 August 2014 (UTC)
I agree with the the gist of the above. To that end, I suggest:
- that a more clean presentation at the beginning would help the layman to understand the concept (e.g. clarifiacation of xyz-space, that the wave propogates in a two-dimensional way %^ds);
- that further description be limited to the topic at hand, i.e. waves in general, and exemplary material be succinct, using offpage links for further explication.
It seems that many of the comments below would be obviated by doing so.
Error in the image File Light-wave.svg On the picture the phase of the Electric component E is the same as the phase of the Magnetic component B. They should differ by 90o in order to achieve rotation of the Pointing vector [E,B] around the direction of propagation. Regards, Boris Spasov, 8/26/2010. —Preceding unsigned comment added by 220.127.116.11 (talk) 21:51, 26 August 2010 (UTC) Hi — Preceding unsigned comment added by 18.104.22.168 (talk) 23:19, 12 March 2013 (UTC)
- Looking back at this; there only needs to be a 90deg phase difference if the EM radiation has circular polarization; for linear polarization there is no phase difference, so the figure seems reasonable. Klbrain (talk) 11:37, 6 June 2017 (UTC)
Confusing in second paragraph. Probably need to state that in seismology, have transverse and longitudinal waves. —Preceding unsigned comment added by 22.214.171.124 (talk • contribs) 20:34, 16 February 2006 (UTC)
Transverse waves travel slower than longitudinal waves ?
I'm not a physicist so I'm not going to edit the paragraph which states that "transverse waves travel slower than longitudinal waves". Maybe someone can expand on it though because I'm left confused by it: I thought light (an electromagnetic wave hence transverse) travels conciderably faster than sound (a longitudinal wave)!
- Don't mix wave speeds for different media and different waves (electromagnetic and sound). Transverse waves travel slower than longitudinal waves in the same medium. --Berland 08:26, 12 April 2007 (UTC)
Transverse waves and polarization definitely relate. The key notion in understanding polarization is to realize that the EM transverse waves are two dimensional. The use of water waves as an example obscures this point. The string example needs to be elaborated, something like below, and needs to be referenced early in the polarization discussions.
.... By moving your hand up-and-down you can launch waves on the string. Notice though, that you can also launch waves by moving your hand side-to-side. This is an important point. There are two independent directions in which wave motion can occur. Further, if you carefully move your hand in a clockwise circle, you will launch waves that describe a left-handed helix as they propagate away. Similarly, if you move your hand in a counter-clockwise circle, a right-handed helix will form. These phenomena go beyond the kinds of waves you can create on the surface of water; in general a wave on a string can be two-dimensional. Two dimensional transverse waves exhibit a phenomenon called polarization. A wave produced by moving your hand in a line is a linearly polarized wave, a special case. A wave produced by moving your hand in a circle is a circularly polarized wave, another special case.
Electromagnetic waves behave in this same way, although it is harder to see. Electromagnetic waves are also two-dimensional transverse waves. This two-dimensional nature should not be confused with the two components of an electromagnetic wave, the electic and magnetic field components. Each of these fields, the electric and the magnetic, exhibits two-dimensional transverse wave behavior, just like the waves on a string. ....
AJim 04:16, 19 July 2007 (UTC)
I think this is an excellent page because it explains transverse waves on a string, where things are clear to visualize. With EM waves things are more complicated. EM waves are transverse in the sense that the polarization is limited to a 2D sub space of 3D space by Gauss's law for magnetism, but they are not necceseraly transverse to the direction of energy transfer (propagation), some EM waves have longitudinal components (electric field in TM guided modes and radial polarized beams near the focus), but even these have no more than two possible orthogonal polarizations.Eranus (talk) 07:38, 15 May 2009 (UTC)
I have been studying the origins of the concept of light as a transverse wave. It appears that both Fresnel and Young, separately, about the same time, while attempting to establish what they called the undulatory theory of light, arrived at the conclusion that plane polarized light could be best understood if the vibration was transverse instead of longitudinal. Their reasoning had earlier been dominated by analogies to sound, and they were concerned to explain the mechanical properties of the medium that they thought they needed to support these transverse undulations. The string analogy to a ray of light appears to have been a key part of at least Young's conceptual breakthrough. Also, I think Fresnel then first postulated and later demonstrated circular polarization (with a Fresnel rhomb) by inference from the properties of a 2-D transverse wave. --AJim (talk) 15:57, 2 June 2009 (UTC)
Speed of logitudinal disturbance in transverse waves
Im trying to get clear in my mind the reason for the fact that longitudinal distubances in transverse waves can actually travel faster (or slower) than transverse fluctuations. Its something to do with the derivative of a function I think but could someone point me in the right direction. Do I start with the wave equation?--Light current 16:22, 16 September 2006 (UTC)
Answer for above question
You are on the right track with the wave equation. The easiest way to visualize this idea is to think about a a wave that travels on a streched string, like the pluck of a harp or the striking of a piano. The wave equation for a traveling transverse wave on a stretched string is
d²y/dx² = μ/T d²y/dt²
Where T = tension on the string and μ = mass per unit length and the wave velocity (longitudinally) = The square root of (T/μ) This equation comes from an analysis of the forces exerted on a very small length of the string as it is bent under tension.
A solution of the above differential equation gives the motion function
y(x,t) = A sin ((2π/λ) (x-vt))
where λ = wavelength of the transverse vibration and v = the longitudinal velocity This allows you to see the difference in the longitudinal velocity and the transverse velocity. The transverse speed of a propagating wave is not constant. In order to see what the maximum velocity of the transverse function is, you have to take a derivative irt time of the above function. that gives you
dy(x,t)= A (2πv/λ) cos ((2π/λ) (x-vt)
Where A2πv/λ will be your maximum velocity in the transverse direction.
The main idea is that the velocity in the transverse direction will change depending on the phase of the wave.The phase is what all the terms in the cos are equal to. When the Y = the maximum height, the velocity will = 0 because it cooresponds to a 90 degree phase. The cos of 90 degrees = 0 so velocity will equal zero. When the wave comes through the equilibrium point transversely, its at its maximum velocity on the Y axis which cooresponds to a phase of 0 degrees or 180 degrees.
The velocity on the X axis (longitudinally) will always be constant because it is determined by the qualities of the medium it is traveling. For a string, it happens to be The square root of (T/μ)
hope this helped.
- Yeah its useful and a good start. THanks--Light current 12:44, 18 December 2006 (UTC)
Why does this article need cleaned up?
This article looks fine to me, can someone suggest a reason why the cleanup tag should still be applied to this page? —The preceding unsigned comment was added by 126.96.36.199 (talk) 06:19, 22 February 2007 (UTC).
- various parts of the article have somewhat strange wording, repetitiveness(if that is even a word), and other small things, I edited some out, somebody else look around for similar stuff. --FranzSS 04:51, 26 April 2007 (UTC)
-->This sentence in the introduction was at best nonsensical, and at worst patently wrong: "A transverse wave has 3 nodes and 2 antinodes." Minor change, but gets my goat.--Jovial Air 21:27, 6 May 2007 (UTC)
"A transverse wave is a moving wave that consists of oscillations occurring" - see Article There is no Wikipedia article for "Transverse El;ectromagnetic Wave". This is the nearest you get. It excludes the TEM step, or pulse, travelling down a USB cable. - Ivor Catt http://www.electromagnetism.demon.co.uk/17136.htm
'Cleaned Up' tag removal
The first paragraph is perfectly clear now and, looking at the revised article, there is no reason for the clean up tag. I suggest it be removed.
Wikipedia really need an entry for the Transverse Electromagnetic Wave. Key information about it cannot be extracted from this entry. Also see electromagnetism.demon.co.uk/17136.htm . Ivor Catt 24 July 2008 —Preceding unsigned comment added by Ivor Catt (talk • contribs) 14:37, 24 July 2008 (UTC)
Removed "No Reference Tag"
Light wave chart is wrong.
The Electric and the Magnetic components of the wave should have phase difference of pi/2. Then the wave can carry energy in the direction of propagation, represented by the Poisson's vector, rotating in the plane, perpendicular to the direction of propagation. firstname.lastname@example.org — Preceding unsigned comment added by 188.8.131.52 (talk) 03:54, 13 March 2012 (UTC)
- Disagree. A phase difference of pi/2 is only needed for circular polarization, not for linear polarization. The electric fields can be in phase, but with orthogonal axes, and then the Poynting vector (I think that this is what you mean) does indeed point along the axis of energy transfer. Klbrain (talk) 11:44, 6 June 2017 (UTC)
Ripples in a pond-transverse wave?
Shouldn't water surface waves also be thought of as longitudinal waves? Motion of individual molecules have both transverse and longitudinal components.184.108.40.206 (talk) 06:42, 8 November 2012 (UTC) Hey — Preceding unsigned comment added by 220.127.116.11 (talk) 01:01, 1 May 2013 (UTC)
Can someone explain why the section on Electromagnetic Waves consists largely of material concerning light rays? The single cited source is to a Zemax software user's guide chapter describing ray tracing. By contrast the corresponding section on the Electromagnetic Radiation page linking to this one is a clearly written description of electromagnetic wave model, being transverse waves, what that means etc.AveVeritas (talk) 12:41, 17 August 2013 (UTC)
The 'Experiment' (I wouldn't use that term, personally; a more appropriate heading would be "In daily life" or "Examples") using the Slinky is ambiguously worded, and could produce transverse or longitudinal waves depending on whichever way the person moving the Slinky would choose to interpret the meaning of the experiment as.
- I completely agree. The Slinky is used - sensibly - in the longitudinal waves article to explain them! A better "experiment" for transverse waves is to waggle a rope or string, which is just what the next paragraph, Explanation, talks about. I have removed the Experiment section as "redundant example is redundant" and a confusing one is a disservice.
- As an aside, it was also out of order. An Explanation should surely come before an Experiment so that you know what the experiment is about. 18.104.22.168 (talk) 10:10, 18 February 2014 (UTC)
- For another example of the Slinky used to illustrate both longitudinal and transverse waves see the Wikibooks entry for Waves/Transverse, Longitudinal and Torsional waves. However they stop short of using the Slinky to illustrate the third type of wave motion they mention, and described as one of the three types in most academic sources I've seen, Torsional Waves. Compare to this use of the versatile Slinky: Understanding Physics: The Properties of Waves Torsional Waves are seen in the type of musical vibration Pythagoras pioneered, according to this paper: Torsional waves in a bowed string. Here's another clear description of these three wave motions and also elliptical waves, such as the clockwise movement of surface water: Online Physics Lab: Wave Fundamentals. Seeing as that last one is a high school physics reference, it's probably a good idea for someone with a proper physics background to begin pages for Torsional waves and Elliptical waves, or at the very least make redirects to appropriate sections elsewhere.
Misleading Example of Ripples in Intro
I'm a n00b, but AFAIK ripples on a pond are surface waves, which are definitely not a subset of transverse waves (or longitudinal ones, for that matter). (Although to be fair, they're mentioned as a way to help visualize the path of transverse waves, and not explicitly as examples of transverse waves.)
Someone should probably replace that with the Slinky mentioned in my previous section on this page, or add a disclaimer of sorts.