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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How does cavity resonance produce EM waves? [closed]

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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1answer
129 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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23 views

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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1answer
60 views

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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28 views

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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1answer
28 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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1answer
34 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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3answers
135 views

Transverse Wave [closed]

Tranverse Wave is travelling in a string.
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181 views

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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3answers
126 views

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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2answers
36 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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1answer
39 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 didn'...
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1answer
62 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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11 views

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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3answers
747 views

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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3answers
58 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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3answers
99 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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1answer
45 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}} u(x+...
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2answers
98 views

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
20 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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4answers
64 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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1answer
35 views

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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2answers
55 views

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 ...
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1answer
130 views

Why are two speakers at the same volume and distance not twice as loud?

If I have two identical speakers facing me which are adjacent to eachother, playing the same music at the same volume, would it be any louder than having just one speaker at the same volume? If not, ...
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2answers
47 views

Is a spring shaped like a sine wave?

It's just a casual observation, so I wanted to check it: A regular spring, when not completely compressed, looks an awful lot like a sine wave. The idea of a circular shape stretched out in the third ...
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2answers
63 views

How does a tranverse wave propagate?

Sound waves can be understood as particles hitting each other and to conserve momentum the vibration travels in air. Each particle transfering it's momentum to the other until it reaches our ears. ...
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0answers
28 views

Why are photonics fibers called band gap fiber?

Why are photonics fibers called band gap fibers? Do the photonic fibers guide light inside the band gap or outside? What creates the band structure?
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18 views

How does an increase in temperature change the width of the central bright for Fraunhofer's single slit experiment?

When coherent light shines onto a metal sheet with a thin slit. There will be an interference pattern with a central bright fringe. If the temperature of the metal is increased, this causes linear ...
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1answer
49 views

Failure of Superposition principle at high amplitudes

Why does superposition principle fail at high amplitudes. Please answer with respect to transverse waves. If possible, plane progressive transverse waves at best.
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1answer
74 views

Why does phase of a wave change after reflecting from a denser medium?

Why does phase of a wave change when reflected from a denser medium, but no change takes place in phase during transmission?
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2answers
29 views

Energy of a wave

Energy density of a wave is given by $$E=\rho\omega^2A^2\cos^2(kx-\omega(t))$$.However for purposes of calculation we use the average of energy.i.e $$E=\frac{\rho\omega^2A^2}{2}$$WHY?
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1answer
42 views

is there explicit eqution between radiation electromagnetic wave and accelerator a charge that has curve moving path?

i had a basis question i read a rule in electromagnetic when a charge is moving and it has accelerator it will emit electromagnetic wave. now i want to find a explicit equation that describe this rule ...
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0answers
29 views

What is the highest frequency for ripples on water

I want to transmit sound vibrations as ripples on water, as an experimental audio delay effect. Can I make ripples at audio frequencies, that will travel over about 10cm or more? How about other ...
3
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1answer
30 views

Confusion about the shock growth

I am studying Hamilton's & Blackstock's Nonlinear Acoustics. One of the essential phenomena associated with a finite-amplitude (unidimensional, planar) sound propagation is building the shock due ...
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11 views

How is the Amplitude and intensity of a sound wave spilt when it splits into three waves with equal energy?

A sound of intensity $27I_o$ is produced at a point. It splits to travel along three different paths. Assume that sound energy is equally distributed among the three parts. Now what is the amplitude ...
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26 views

How do I find the general equation of a wave propagating through space?

I came to know that general equation of any wave is a function of time and another parameter which depends on type of the wave. According to my textbook, definition of wave is propagation of a ...
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2answers
660 views

What makes a wave dispersive?

Water waves are dispersive ( longer wavelengths travel faster ) but sound waves in air are not, otherwise we would listen first the high frequencies and the low frequencies after. What decides if a ...
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3answers
78 views

Derivation of the group velocity

I know that the group velocity of a light pulse is defined as $$\begin{split}v_g&=v_p\left(1+\frac{\lambda}{n}\frac{dn}{d\lambda}\right)\\ &=\frac{c}{n}\left(1+\frac{\lambda}{n}\frac{dn}{d\...
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1answer
84 views

Why do water waves with longer wavelengths travel faster?

When wind blows over the sea, it excites a range of wavelengths. Why do longer wavelengths travel faster?
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1answer
28 views

Pressure Inverting Reflection of a Sound Wave

How would the frequency and energy of a pressure inverted sound wave compare to the frequency and energy of the original sound? Would it sound any different?
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1answer
67 views

Interference of light waves question

We were recently asked to solve a question in class which goes as follows: In a modified Young's double slit experiment, a monochromatic uniform and parallel light beam of wavelength $6000$ ...
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3answers
301 views

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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22 views

What is the relationship between the size of a slit and wavelength in diffraction? [duplicate]

Almost everywhere I see the statement that diffraction gets stronger when the size of the slit is comparable to the wavelength. I would just like to know the logic behind. Could anyone help me please? ...
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18 views

Scale analysis for the vertical component of the Boussinesq equation to obtain a complete hydrostatic relation

This is actually an exam question which i have been trying to solve for my studies. Consider the Boussinesq vertical equation: \begin{align} \frac{\partial \widetilde{w}}{\partial t} = - \frac{1}{\...
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24 views

Intensity of interfering light waves

I had a conceptual question above light wave interference. Suppose that two light beams, each of an irradiance $I$ interfering on an area $A$ of a screen, such that all of the light from each beam ...
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1answer
25 views

Progressive and Stationary Waves Amplitudes confusion

In my mechanics lecture, my professor mentioned that standing waves have nodes and antinodes, which is correct. Then he mentioned that in progressive waves, all the points have the same amplitude. ...
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1answer
81 views

What causes electromagnetic waves to propagate in free space?

In free space, $\rho=0$ and $J=0$, so there are no electromagnetic sources/sinks. Maxwell's equations thus reduce to: $\nabla\cdot E = 0$ $\nabla\cdot B = 0$ $\nabla\times E = -\frac{\partial B}...
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1answer
56 views

Can there be a wave function that is physically possible but is non differerentiable (maybe even non-continous)?

The definition of a wave function demands continuity and differentiability so that it can satisfy the Schrödinger Equation. My question is whether this assumption is necessary for reality. Does ...
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1answer
28 views

Diffraction grating (finding number of emission lines)

I came across a question on isaacphysics.org where youre given information about a diffraction grating, the spacing of the gaps and the colour and location (in degrees) of 8 different maxima, of four ...
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1answer
47 views

2D standing wave

When we have 1D standing waves, we can write them as the sum of two propagating wave in opposite directions that give the formula $\sin(kx)\cos(wt)$. When I try to do this for 2D waves (I mean 2D by ...