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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Diffraction wavelength relationship [on hold]

This question appears somewhat similar to other questions asking about why wavelength affects diffraction (a concept which I'm still not 100% sure on...) however my query is different and not answered ...
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653 views

In wave motion of a string both kinetic energy and potential energy are minimum at $y=y_\text{max}$ then why does the string comes down again?

In wave motion of a string both kinetic energy and potential energy are minimum at $y=y_\text{max}$ then why does the string comes down again? As everything in tries to attain lowest energy possible ...
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Vibrating string - wave speed and tension relation

I was studying vibrating strings and in my teacher's notes I found that, generically, if I change the tension on the string by $\Delta T$ then, the speed percentage change can be written as: ...
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24 views

Which information do we get from the phase spectrum about the wave?

Let a wave is represented by an equation $$y=f(t)=10\sin(\frac{2\pi f_1t}{T} + \pi/6)+5\cos(\frac{2\pi f_2t}{T} +\pi/3)$$. Here, let us take $f_1=10 ,f_2=5 ,T=100$ Then, from the Fourier transform ...
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What Exactly is a Shock Wave?

The Wikipedia defintion of a shock wave pretty much sums up all I've found online about what a shock wave is: A shock wave is a type of propagating disturbance. Like an ordinary wave, it carries ...
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17 views

Medium particle velocity vs wave velocity

It is said that wave may have a uniform velocity. We could think of the time when exactly the 1/3 th wavepulse has finished pasing through this point, and 2/3th numbered wave pulse would do this ...
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28 views

Phases and sinusoidal waves

When we're talking about a wave, just a singular sinusoidal wave, what exactly is a 'phase'? I came across a question that gave values of frequency ($550$Hz), and speed ($330$m/s). The question then ...
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157 views

Derviation of group velocity

I am working thru a derivation of the group velocity formula and I get to this stage: $$y=2A\cos(x\frac{\Delta K}{2} -t\frac{\Delta \omega}{2})\sin( \bar k x-\bar \omega t)$$ Then all the derivations ...
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163 views

Path Difference Due to Angled Incident Light

If light incident on a diffraction grating makes an angle $\alpha$ with respect to the normal to the grating, show how $$m \lambda = d\sin\theta$$ becomes $$m\lambda = d[\sin(\theta - \alpha) + ...
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382 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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1answer
31 views

Why does the classical Doppler formula make a distinction between movement of the source and movement of the receiver?

I've tried rewriting the Doppler formula to include only the relative velocity between the source and the receiver of sound waves. However, when I compare the results with the results of the formula ...
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36 views

Can gravitational waves interfere polarize or show any other properties of stndard waves

Is it possible for gravitational waves to be able to produce phenomenon such as interference and polarization etc. which are observed in standard waves. Also is it possible for gravitational waves to ...
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Rope waves with a twist

In the picture you see a person walking a slackline. A slackline is a tensioned flatband of polyester. Typical tensions are between 1 kN to 15 kN depending on the length of the line. The lines are ...
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631 views

Which formula for the de Broglie wavelength of an electron is correct?

So, I have my exams in physics in a week, and upon reviewing I was confused by the explanation of de Broglie wavelength of electrons in my book. Firstly, they stated that the equation was: $\lambda = ...
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1answer
166 views

Energy and the modes of standing waves

If you induce a higher mode in a standing wave, does the wave then carry more energy? If so, does that differ for a mechanical or EM wave? (Perhaps I should elaborate on why I am asking this ...
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Explain quality factor and bandwidth [duplicate]

Can anyone explain concept of quality factor and bandwidth with a mechanical example?
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36 views

Why does thicker aluminum do better at reflecting wifi

I have performed a experiment based one the ability of aluminium reflecting wifi radio waves. I have found out that the more aluminium foil i put on my reflector, the better result I can get. I did up ...
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88 views

Is meters per second equivalent to seconds per meter?

I know this question is probably ridiculous, but bear with me for a moment. This thought emerged while I was converting between nm and wave numbers ($\rm cm^{-1}$). In order to prove this conversion, ...
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How does cavity resonance produce EM waves?

My understanding is it acts like a capacitor and inductor in a loop. The capacitor releases stored energy which is absorbed by the inductor through a magnetic field which then returns it to the ...
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126 views

A plane electromagnetic wave - phase change - amplitude

A plane electromagnetic wave has the shape: $\vec{E}(\vec{r},t)=E_0\cdot cos(\vec{k}\vec{r}-\omega t)\cdot \vec{e}_y$ $\vec{B}(\vec{r},t)=(B_1\cdot cos(\vec{k}\vec{r}-\omega t)+B_2\cdot ...
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Solving traveling wave using the shooting method

The spatially-dependent Hodgkin-Huxley equation for a cylindrical dendrite or unmyelinated axon: where $\frac{a}{2\rho}\frac{\partial^2V}{\partial x^2}$ is a diffusion term $a$ is the fiber radius, ...
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110 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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Simple harmonic waves

When a simple harmonic progressive wave is travelling through medium,then each succeeding particle lags in phase before the preceding particle.Can anyone expain how does it lag? Thanks…
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Plucking Guitar Strings [closed]

I was given this prompt: A musician frets a guitar string of length 1.5 m at x = 0.28 m with one finger, and simultaneously plucks the string at x = 0.14 m with another finger (raising it to a height ...
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177 views

Acoustical wave equation from Hamilton's principle

It is common to show the features and power of the Hamilton's principle by deriving the equation of vibrating string, membrane etc. using this principle. But I have never seen that used for deriving ...
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20 views

Is it possible to low pass filter the amplitude of a sound wave?

Is it physically possible to block or attenuate noise above a certain amplitude, but leave other lower amplitude noises unhindered?
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21 views

Can you have a problem with a Dirichlet boundary condition but with waves that reflect off the boundary?

Say we are looking for a solution to the Helmholtz equation $$(\Delta + k^2) u = 0,$$ in in the upper half space ($y > 0$) in 2D with a Dirichlet boundary condition on the $x$-axis, that is, $u(x, ...
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Transverse simple harmonic wave travelling in a string [closed]

This question came in my exam. My Attempt: I thought that the tension will not vary in the string because since we know that velocity of wave in a string is given by $$v=(T/m)^{1/2} $$ where $v$ ...
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25 views

How to solve the following wave equation? [closed]

We have paraxial beam propagating in a uniaxial anisotropic media. When such is the case wave can be divided into two orthogonal parts: Ordinary wave beam Extraordinary wave beam. The ordinary ...
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1answer
345 views

Particle displacement at a rarefaction or compression

In a longitudinal wave, why is there zero particle displacement at a compression or rarefaction and maximum displacement at a point pi/2 from it? Shouldn't it be the other way round?
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Why is the Plane progressive wave equation $y= a\sin (kx-wt)$ for positive direction of x-axis?

Likewise, why is $y= a\sin(kx+\omega t)$ for negative direction? What is the basis/derivation for this?
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Explanation of the 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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31 views

What is the player's role in the functioning of a theremin?

I recently see a video on how the theremin works, and wasn't satisfied with the answer. I watched around, but they all seem to give the same explanation. A diagram as below is given, and it is ...
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Don't all waves transport mass?

How do matter waves not transport mass? I know that matter waves are associated with moving sub-atomic particles(which is insignificant for macroscopic particles). If a wave is associated with a ...
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1answer
29 views

Wave Velocity vs. Phase Velocity

I am trying to understand the difference between 'wave velocity' and 'phase velocity'. I know that generally they are equal, but when is that not the case? I, of course, tried to google it, and ...
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41 views

How do waves transfer mass?

A similar question was asked here, however the discussion was led astray by involving the equation $E=mc^2$. I know that waves transfer energy, but do they transfer mass? And, if they do, what would ...
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Energy density of a transverse

I'm finding it hard to understand the concept of energy density of a transverse wave. I know the formula, but I can't quite get my head around it. I know energy density is energy over volume, but ...
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1answer
39 views

Derivation of the wave equation from Hooke's law- Generalization question

Following the derivation on the relevant Wikipedia page, I am having a bit of trouble moving from the following line, with the case of 3 particles in a row: $$ \frac{\partial^{2}}{\partial t^{2}} ...
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20 views

Is the speed of a wave determined by the medium in which it travels, the frequency of the source, or both?

I know that for a string of linear density $\mu$ and tension $T$, the wave speed is given by $v=\sqrt{\frac{T}{\mu }}$. Additionally, the speed of any sinusoidal wave is given by $v=\lambda f$. My ...
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70 views

An experiment to show sound waves

My 6 year-old son asked me to explain the sound barrier. I think I'm ready to explain, but I wanted to know if I could add a little homemade experiment to show visually how soundwaves are generated. ...
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Is it better to call the doppler effect a change in wavelength or frequency?

Why is it preferable to say that the doppler effect causes a shift in frequency rather than a shift in wavelength? I often read on websites that they define the doppler effect as a change in ...
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Do mechanical waves also carry momentum as well as energy? [closed]

I have read that electromagnetic waves carry momentum because they carry energy, while energy is equivalent to mass. So they carry momentum. But this explanation is in the context of special ...
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1answer
15 views

When should I use the phase constant in the equations of waves?

In the equations of Waves, I find that somewhere they have used the phase constant and somewhere haven't. While deriving the formula of standing wave they assumed two equation as $ y_1\; =\; y_0\, ...
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55 views

Is the speed of sound in air constant?

In Optics lecture we took a formula for the speed of a wave which is: $$ v=\frac{\omega}{k} $$ where $\omega$ is number of complete vibrations per second: $$ \omega=\frac{2\pi}{\tau} $$ and: $$ ...
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Why a ship can't pass through its own wave?

This is a photo of a container vessel. All container vessels are long because they are cruising at high speeds. When a ship is sailing it creates waves. When the wavelength of these waves equal the ...
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2answers
70 views

Is Huygens's Wave Theory still correct?

We have to study on details about Huygens's Wave Theory though we have Electromagnetic theory, quantum theory today. Is it still correct or not?
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Problem in understanding the interpretation of $-T_0\frac{\partial\psi(z,t)}{\partial t}\,.$

I've been reading in Frank S Crawford's Waves, travelling waves and reflection. Here in the following quotes, the author interprets the term $\frac{\partial \psi(z,t)}{\partial z}$: The power ...
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Conservation of energy in a sound wave

I have two ultrasonic transducers, an emitter and a receiver, and I'd like to know how the energy of the spherical wave is conserved. I guess the energy is proportional to its amplitude and it ...
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Is the wave equation a periodic wave equation?

I have seen that in the derivation of wave equation, they always use the periodic property of waves in the derivation. But what about non-periodic waves? Do they have some different wave equation? Is ...