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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Why is sound intensity defined as the product of pressure and particle velocity?

The intensity of a sound wave is defined to be $$\vec{I}=p(x,t)\vec{v}(x,t)$$ I can see that the units on either side of the equation balance, but I can't find a derivation online that shows why $\...
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Physics 3 recommended book with solutions [duplicate]

I'm new to this forum and wanted to ask for a recommendation for a book which has these subjects with problems and solutions:(if this is not a valid question please tell me) -Intro to Waves -Fourier ...
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63 views

Matter wave's properties

The matter waves are not electromagnetic waves, so, can they be coloured like the visible region of the electromagnetic wave spectrum? Any examples as such?
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Standing Waves in a String of two Linear Densities

Given a string with sections of two linear densities like this: Does the point where the two linear densities meet have to be a node if a standing wave is produced? Are there alternatives? Could I ...
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59 views

Do photons traverse through the vacuum of outer space as a helix? [duplicate]

I’m trying to understand “Electromagnetic waves”. If electromagnetic waves traverse as a helix then do photons traverse as a helix?
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3answers
154 views

Why is it said that standing waves do not transfer energy?

The author of my physics textbook writes that standing waves, unlike travelling waves, do not transfer energy. He says that this is because a standing wave is composed of two travelling waves carrying ...
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60 views

Why do pulses get reflected by a fixed end?

Consider the case where a pulse hits a fixed end. I want to know the physics behind the following two phenomena 1) Why does the pulse get reflected? 2) Why does the pulse get inverted? I somewhat ...
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28 views

Amplitude-Modulated Wave in a Dispersive Medium

Amplitude-Modulated Wave in a Dispersive Medium. An amplitude-modulated wave with complex wavefunction $a(t)=[1+m\cos(2\pi f_st)\exp(j2\pi\nu_0t)$ at $z=0$, where $f_s\ll\nu_0$, travels a distance $z$ ...
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28 views

Help understanding the wave number in light

For my final optics project I want to implement the beam propagation method using Fourier transforms. I came across the following document http://ecee.colorado.edu/~mcleod/pdfs/NMIP/lecturenotes/NMiP%...
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54 views

Classical wave equation - validity

I know that classical wave equation carries for spherical wave fronts. In addition, Huygens' principle states that any wave front is a superposition of many spherical wavelets, so why does the ...
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19 views

When EM waves travel through a material with refraction index n, is the formula $\lambda = \frac{c}{n \cdot f}$ correct?

When EM waves travel through a material with refraction index n, ist the formula $\lambda = \frac{c}{n \cdot f}$ correct? c is the speed of light in vacuum and f the frequency of the wave. Thank you!
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38 views

Does frequency of a vibration wave of a cantilever depend on its deflection?

cantilever= a beam fixed at one end only deflection is the initial displacement of the free end. the beam is let go when the free end reached its position it will vibrate, does the frequency of ...
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Standing waves arbitary frequency

Suppose I have a string that is fixed rigidly at one end. Now when I start making wave, it will get reflected and should lead to standing waves (Mathematically and by visualization), but then we have ...
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29 views

1D transmission lines wave equation solution

you may know that the solution of 1D wave equation by d’Alembert is F(x-ct)+F(x+ct) and my question is that like is this F(x-ct) at transmission lines only the equation of one forward going wave that ...
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44 views

What is the significance of a function being a solution to the wave equation?

I understand how the wave function is derived. I also understand how to check if a function serves as a solution to the wave equation: If a function is solution to this wave equation, what does ...
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2answers
97 views

Standing wave on a circle [closed]

Suppose that we have a standing wave on a circle. I heard that by gradually increasing the radius of the circle, the wavelength will also increase to keep the standing wave. Is it right? If yes, what'...
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1answer
50 views

How fitting is the sound wave (transverse wave) propagation model? (for the layman)

Air is a gas, then how is sound wave propagation possible? I mean, gas particles have a tendency to travel in a straight line, so how does a sound wave occur via compression and rarefaction? Most ...
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44 views

Is it possible to generate deep infrasound with subwoofer and a pipe?

I would like to check if infrasound noise can make people feel weird (as in a "haunted" house). Some people claim that noises of such frequency may be the cause of "paranormal" sensation in humans. ...
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92 views

Is double slit interference due to EM/de Broglie waves? And how does this relate to quantum mechanical waves?

I'm really confused about the fact that there seems to be two types of waves at play: the EM wave, which I understand to be an actual fluctuation of EM fields in space, and this other type of bulk "...
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43 views

Distinguishing transverse and longitudinal from wave equation

Can we distinguish if a general wave or disturbance $f$ (not necessarily electromagnetic) which satisfies the wave equation \begin{equation} \frac{1}{v^2}\frac{\partial^2 f}{\partial t^2} = \frac{\...
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86 views

Complex resonant frequency not resonant without imaginary part. So can I still just take real part as solution?

I am working with a matrix on a harmonic oscillator problem and the lowest (absolute) frequency $\omega_0$ where the matrix becomes singular is the resonant frequency. Now I obtained this frequency ...
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1answer
67 views

LinAc standing wave

I have a question regarding Linear Accelerators (Linacs): Originally, traveling HF waves were used to accelerate electrons inside a Linac. You can see a sketch in the following picture. The further ...
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45 views

Frequency of wave related with the speed of wave

Today I am studying about waves. So, we learn the formula "speed = frequency * wavelength". There is a question come out in my book If the frequency of water waves is decreased, what will happened ...
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how does reflection takes place in an open organ pipe [duplicate]

I'm interested to know how is there reflection without any boundary in an open organ pipe. It could be understood in closed one .
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43 views

What is difference between standing and non standing waves?

While reading about waves it was written in my book that standing waves have varying amplitude but constant angular frequency or time period. But I am not able to exactly differentiate between ...
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1answer
57 views

Finding mass attached to the string

I'm given the following problem: One end of a string with a linear mass density of 7.60* 10^-4 is connected to an oscillator with a frequency of 50.0 Hz. The other end is connected to a hanging ...
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34 views

Front velocity and Superluminal group velocity

In some cases, according to Wikipedia, the envelope of a gaussian beam can go faster than speed of light hence leading to superluminal group velocity. However, the signal/energy still propagates at ...
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Can every single sound ever made(from the beginning of time) be recreated again?

Sound is a wave and energy decreases as $1/r^2$ . The intensity of sound is proportional to $(amplitude)^2$ of the wave. So if we amplify the wave with some instrument then we can hear every single ...
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26 views

Regarding wave displacement equation [duplicate]

in some textbook i read that one can describe wave displacement by y(t)=Asin(ωt+ϕ) and y(t)=Acos(ωt+ϕ) . i know both these terms are periodic but how one can use any of these equations in numericals ...
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24 views

The initial conditions for the harmonic travelling waves

I'm given the following problem: For a harmonic travelling wave travelling in the positive direction, the initial transverse speed is 3 m/s and the initial $y$ displacement or transverse ...
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18 views

Relevant Archemidan Spiral Theorems: An Enquiry

Basically what I'm doing is investigating the solar wind's outflow. As part of this investigation is included a fairly crude application of a more complex outflow solution to that of basic archemidian ...
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1answer
187 views

Sound Intensity and Frequency Relation

The intensity of a wave is proportional to the square of the amplitude of the AND the frequency of the wave given by the equation: Now when talking about sound waves the sound level of a noise (...
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7answers
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What's the difference between mechanical and electromagnetic waves? [closed]

I have a life science degree and even worked in research for a few years. So I feel I should be able to answer this question for myself, but yesterday my daughter blindsided me by asking why, if sound ...
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96 views

Difference between a wavevector and wavefunction

I often see both terms used in textbooks, but I am not sure whether I understand the difference between them. Both describe the state of a system, however, they seem different in some ways. From what ...
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35 views

factors that affect energy of a sound wave?

Putting a lot of energy into a transverse pulse will not effect the wavelength, the frequency or the speed of the pulse. The energy imparted to a pulse will only affect the amplitude of that pulse.why ...
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55 views

Light waves and water waves

I have an idea and i would like to have more information: If I drop a stone in the water some rings or waves will appear. Those rings are made of water and are behaving that particular way because of ...
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42 views

What is the actual meaning of magnetic field and electric field in Electromagnetic waves?

I know that electromagnetic waves are composed of electric field and magnetic field but I don't understand what magnetic field is. Would you help me understand its physical meaning? What is the ...
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Is frequency at normal inversely proprtional to wavelength?

since speed of sound is constant for normal conditions(conditions where speed of sound is normal) , can anybody provide me the mathametical proof of why frequency is linearly and inversely ...
2
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1answer
134 views

Normal Modes for Standing Waves in 1-D Acoustic Ducts with Arbitrary (but real) Impedance Jumps

Let's say we have a 1-D duct, such as this: Where $Z_i \equiv \frac{P}{US}$ is the acoustic impedance, L is the length of the duct in question, and S is the area of the cross-section. In general, ...
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51 views

group velocity of acoustic waves

One can find the sound speed for the acoustic waves as follows: $\frac{\partial p}{\partial t} = -\nabla \cdot \rho \vec v$ (1) $\rho (\frac{\partial \vec v}{\partial t} + (v \cdot \nabla)\vec v)= -...
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Can you simulate a Michelson-Morley experiment with sound?

Is it possible to make a MME with sound waves? Suppose we travel on a rail platform with two "mirrors" that reflect sound, what parameters would we need to simulate the light experiment? would it work ...
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83 views

What field property may allow faster than $c$ speed?

What field property may allow faster than $c$ speed? Is there theoretical field or what property it needs to have to allow wave speed larger than $c$? What is the speed of the gravitational wave? Is ...
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Which came first - definition of wave or wave equation? [closed]

In an interview, I was asked to define what a wave is. I replied that it was a sort of disturbance which propagated. Then he asked how I could identify what a wave would be like. I said that the ...
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1answer
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Amplitude at successive wavefronts?

Consider spherical waves emanating from a point source initially the amplitude is A, as wave travels forming wavefronts will the amplitude of each point in all the secondary wavelets be the same and ...
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How is wave equation equivalent to the Turing reaction-diffusion equation with 3 species?

I was reading the paper, "Critical waves and the length problem of biology" by Robert B. Laughlin. He mentions a point like this in it : "This wave equation is equivalent to Turing Reaction-diffusion ...
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1answer
32 views

Velocity of propagation of an EM field in vacuum

I am asked to find the speed of propagation $\vec{v}$ of an electromagnetic field, in a region of empty space. The magnetic field is described by $\vec{B} = B_0e^{ax}\sin{(ky-\omega t)} \hat{z}$. I ...
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1answer
82 views

Why is root mean square pressure used in the definition of sound pressure level?

I dont understand the way we measure loudness. I know that it is in some way related to the magnitude of pressure variations. please help me figure out where my understanding fails. Let $p(t)$ be the ...
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Why invariance holds for the electromagnetic waves but not for the mechanical waves?

Why the electromagnetic wave equation provides a wave with constant speed in all reference frames, but the mechanical elastic wave equation (from linear elasticity) does not? The electromagnetic wave ...
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1answer
89 views

Why does compton scattering provide evidence for the particle nature of light?

I understand that compton scattering is modeled as a collision between a photon and an electron, but why does this conclusively prove that light can act as a particle? Why couldn't the same ...
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Can a system be engineered to cause a standing wave resonance with gravity waves? [closed]

Thank you Docscience for helping me adjust my question in a better direction. My interest has been sparked by getting Into the chapter of waves in physics class and of course the new discovery of ...