Waves are disturbances that propagate through space and time. Classically, they travelled through a medium, disturbing the particles but not changing their mean position. Electromagnetic waves/particle-waves need no medium; they are disturbances in their respective fields.

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In order for the occurence of beat, why is it compulsory that $|{\omega_2 - \omega_1}| \ll \omega_1 + \omega_2$?

As A.P.French in Vibrations and Waves writes, The beating effect is most easily analyzed if we consider the addition of two SHM's of equal amplitude: $$ \mathbf{x_1} = \mathrm{A} \cos{\omega_1 .t} ...
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Relation between sound waves and air molecules

The following was written in my book When sound waves travel in air, air molecules do not move. When wind blows,air molecules move. This produces variation in velocity of sound waves. The first ...
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how to measure the wave emitted from some particles after input sine wave into the particle

which waves can be input into the particle? is it sine wave? is the wave emitted from the particle after input wave into the particle different? if want to measure the output wave, how to use math ...
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How much energy and momentum carried by a mechanical wave?

Let's assume there is a wave spreading across in a substance. Described by some partial differential equation. How can I calculate the momentum and energy carried by this wave? Or maybe the energy ...
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1answer
78 views

What is the advantage of using exponential function over trigonometric function in analyzing waves?

A.P.French in his book Vibrations and Waves writes: . . . Why should the exponential function be such an important contribution to the analysis of vibrations? The prime reason is the special ...
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Physical intuition for the solutions of the wave equation

I have been studying the wave equation in $\mathbb{R}^n$ for the cases $n=1,2$ and $3$. In the three cases, working all over $\mathbb{R}^n$. That is: $u_{tt}(x,t)=c^2 u(x,t)$ for $x \in ...
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18 views

Is the oscillation of all particles for stationary wave equal?

Is the oscillation of all particles for stationary wave equal? I think the point of nodes for stationary wave never oscilliate. Is this idea true?
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1answer
38 views

Huygens' Principle During Reflection: comparing wavelets from before reflection with wavelets from during reflection

I was recently reviewing geometric optics, during which I read about Huygens' Principle and how it could be used to prove the Law of Reflection from the "light is a wave" viewpoint. I'll quote what I ...
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2answers
60 views

Does sound have a “louder” direction?

I have a question about the propagation of sound waves. We have two TV's in our house that are almost right on top of each other. One is located on the first floor and the other one is located on ...
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Acoustics - Phased Arrays

Has any work been done on phased arrays of speakers and microphones on the walls of a house being used to; * create maximas of ultrasonic waves at a given point in a room. * software to ...
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1answer
23 views

Besides vortex rings, are there other types of traveling waves that can carry matter as well as energy?

Vortex rings are a special soliton wave that are known to carry matter over a distance as well as energy. This can easily be demonstrated using a cardboard 'vortex canon' filled with smoke. The smoke ...
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72 views

What is the difference between real and imaginary parts of a sinusoid?

Can somebody explain, without using complicated mathematical formulas, what do real and imaginary parts of the sinus function represent? And what are relations between them? I cannot understand why ...
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39 views

Waves - determining whether a given formula represents a wave

Well the basic formula of a wave needs to contain $$y(x,t) = f(x \pm vt)$$ where the sign depends upon the direction of propagation of the wave. However, not every function in the form $y(x,t) = f(x ...
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52 views

What is the physical significance of the negative amplitude of a light wave?

I want to understand what is the physical significance of negative amplitude of a light wave? In an ac electrical circuit, I understand that negative amplitude signifies the amplitude measured when ...
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3answers
94 views

Surface waves on Dr. Miller's planet

In the movie 'Interstellar', the crew land on a water world orbiting a black hole. The gravity is greater than that of Earth and there are huge surface waves present in the ocean that they land in. ...
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Pressure evolution equation atmosphere

Working on gravito-acoustic wave propagation in a windy and viscous atmosphere I tried to recover the pressure evolution equation. My starting point was the adiabatic state equation : ...
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9 views

Sonic Attenuation in a Steel Plate [on hold]

What is the formula for sonic attenuation in a steel plate of some thickness. The slowness of the steel, the distance and and the thickness are given. The frequency might be 100 KHz.
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49 views

Wavefront of a wave?

I'm trying to understand the idea behind a wavefront in a visual manner. Take a look at these surface waves in water Now imagine if I sliced it twice, through the origin, in a vertical plane. I'd get ...
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3answers
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Why do these standing waves appear to be traveling?

Take a look at this video: https://www.youtube.com/watch?v=TKF6nFzpHBU You would expect guitar strings to produce standing waves, and in fact, the upper, thickest string does often produce long, ...
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1answer
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Transmission line given SWR and Wave Lenght, calculate Reflexion Coeficient [closed]

Given a transmision line with SWR = 7, we know in Wave_length/4 there is a maximun of the stationary wave. What is the reflexion coefficient in z=0¿? I also have another example with SWR = 7 too and ...
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2answers
148 views

Physics of guitar strings

Guitarists normally press down hard on the frets and then pluck a string to obtain a note. However, one can also create notes by just touching the string above a particular fret and plucking. For ...
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2answers
67 views

What is the wave propagated away from an impulsively excited spherical shell?

Consider a spherical shell of radius $R$ centered on the coordinate origin, and an impulsive excitation $\delta (t)$ distributed over its surface ('ie. a single layer'). Each point on the sphere’s ...
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How to derive the Sperically symmetric Wave Equation (in spherical coordinates) using first principles? [closed]

I want to use first principles (of mass and momentum conservation) on a spherical shell and derive the wave equation given below, where $p'$ is the pressure perturbation : $\frac{\partial^2 ...
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1answer
29 views

Phase change on reflection only 0 and $\pi$ allowed

We know that when a wave on a string is reflected from a hard boundary, the phase change is $\pi$, and from a soft boundary, the change is 0. My question is: this two conditions (hard and soft ...
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1answer
26 views

Pressure wave in a cup of tea casued by a bubble burst

Assume there is a cup of tea with bubbles formed on its surface by the inner wall of the cup. If one of the bubbles bursts, it causes a wavefront travelling on the surface of the tea. Is this wave ...
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13 views

Heat wave containing particle and wave like properties [duplicate]

I see heatwaves occur on the road and was wondering if that is visible motion of wave like properties involving particles.
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1answer
22 views

How to draw waves in X and Y position like this oscilloscope example?

I would like to know how to "draw sound" so i could achieve shapes like the ones in this video: http://www.modularsynth.ru/en/2014/01/24/ed120_chaotica/ I have programming background ( as in: i ...
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68 views

Is light amplitude spacial?

In diagrams I often see light waves depicted as little sine waves that travel through space. And often when describing polarizers, the explainer will angle their hand to show the angle of ...
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1answer
43 views

Damping of not harmonic waves

You pluck a (guitar) string so that you create a wave with harmonic frequency and a wave with not-harmonic frequency. Which one will be heard longer? Why? Or ask it differently: Is the wave with ...
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Wave theory numerical problem [closed]

Calculate the velocity frequency and wavelength of sodium D-line(lambda=589 nano meter) of light passes through a species whose refractive index is 1.43.
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60 views

Resultant frequency if 3 harmonic notes (a chord) is played

If I know the frequency of individual notes being played (let's assume D, F# and A), how do I determine the final frequency if they are played (nearly) simultaneously as a chord. To put the problem ...
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34 views

Huygens and philosophy of the slit

A single (narrow) slit diffraction pattern, can be explained/described classically with Huygens' principle (1678), and quantum mechanically with the Uncertainty principle. If the pattern on the screen ...
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1answer
48 views

Why does sound become louder and increase frequency if I give it a narrow path?

If I put my hand over the speaker of my phone like in the picture, I can clearly hear my music amplified, why does this happen? The only cause I can think about is the fact that all the intensity ...
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How quickly is motion transferred in a solid object?

Just for example: assume an iron bar one foot in length. If you push on one end, the entire bar will move. This seems instantaneous. but actually, from my understanding, the atoms all push against ...
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3answers
80 views

Is it theoretically possible to project sound in a line, like flashlights?

I was wondering if there is a way to project sound waves on a particular point, like a laser? So that you can you can privately send a voice message to a specific person in crowd. The very first idea ...
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0answers
31 views

Ripples of flowing water on a smooth road surface [duplicate]

Yesterday some friends and I were walking in the rain. We noticed that, on a smooth tarmac road surface, the sheet of water flowing down the road was forming ripples as it went. Why was it doing ...
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1answer
33 views

If wave speed is dependent on medium only, then how to reconcile $v\propto f$?

I have read and learnt in many places that velocity of a wave depends only on the medium through which it travels. It is clear from this that the velocity of a wave doesn't depend on the frequency of ...
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1answer
41 views

Light Lab Misunderstanding. Please help

For a Physics lab, this question was asked "As you learned, the wavelength and the separation of the sources affect the number of nodal lines produced. Using your results from steps 2 and 3, determine ...
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1answer
30 views

How does a longer wavelength penetrate deeper with Rayleigh waves?

I'm struggling slightly to understand this idea. I've slowly been building up an explanation, so at this stage it might be just some confirmation I'm looking for, but also some guidance if I'm off ...
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Circular standing waves musings [closed]

I'm wondering if there is a mathematical model under which particles can be described as spherical waves with he properties that they can move and repel and attract other such "particle-waves" under ...
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1answer
23 views

Electron orbitals and the circular membrane vibrations

I just stumbled across the fascinating analogy between electron orbitals and the fundamental waves of a circular membrane in Wikipedia. Now the weird and arbitrary looking orbitals don't look so ...
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1answer
34 views

Watertank waves

Say we have a rectangular tank of water and we push it lengthwise. Suppose the surface stays planar. What would be the trajectory of the centre of mass?
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Walter Lewin's physics lecture 8.03 Waves and Oscillation [closed]

Does any of you have the files (lecture notes, assignments, exams) of Walter Lewin's course on Waves and Oscillations? I used to learn from them and it helped so much. Thanks before
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3answers
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Can “particle” waves break as ocean waves do?

I have heard about electrons surfing on wake fields which got me thinking. Are there analogs to reefs for these waves and can these waves break as ocean waves do when they hit a reef?
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How do electromagnetic waves travel in a vacuum?

This is perhaps a total newbie question, and I will try to formulate it the best I can, so here it goes. How does an electromagnetic wave travel through for example, the vacumm of space? I usually ...
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What is the source of water and waves on the water planet in the movie Interstellar?

We will ignore some of the more obvious issues with the movie and assume all other things are consistent to have fun with some of these questions. Simple [hopefully] Pre-questions: 1) If the water ...
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1answer
101 views

about to create a standing wave

I think partial of this question being asked before but I have some other doubts.As shown in this post how to add two plane waves if they are propagating in different direction?, reading the third ...
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3answers
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Frequency of Sound Waves

Is the frequency of the echo (resulted from the reflected sound wave) equal to the frequency of the original sound wave?
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The amplitude of oscillations in sound waves

How can the amplitude of molecules displacement be measured in a sound wave? How can the amplitude of the pressure fluctuation be measured in a sound wave? What are the difference between these two ...
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Electromagnetic Waves Speed

What is the relationship between the speed on the electromagnetic wave and the density of the medium in which the electromagnetic wave travel through?