Waves are disturbances that propagate throush 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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What are natural sources of longwave radiation

I am studying now the Earth radiation balance and I came across the question regarding the sources of the long-wave radiation on earth surface. The only source of theses wavelengths indicated in the ...
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What is the difference between phase difference and path difference?

I have learnt that path difference is the difference between the distance travelled by two waves meeting at a point. If that is path difference,then how will one know what is phase difference and how ...
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57 views

What are the properties of the Electromagnetic wave $E=E_0e^{-i\omega t}$

My question is, whether this definition $E=E_0e^{-i\omega t}$ includes that it is a plane wave, since I am confused by the fact that we do not have any dependence on the position. So about what kind ...
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108 views

Uncertainty and wave-trains

My textbook and the following extract from feynman's lectures present the same idea regarding wavetrains and uncertainty in their wavelengths. Why is it that a wavetrain confined to some space has an ...
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113 views

Frequency calculator

I have a bunch of readings of a wave consisting of volts and time. I need to calculate the frequency of the biggest wave, but i'm not sure exactly how. From what I've researched I'm thinking I need to ...
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152 views

Can we see light as it 'interferes' with itself and produces the characteristic double-slit pattern?

This TED talk suggests that we can now watch as a beam of light propagates through a bottle filled with water. My question is: can we use this new technology to perhaps 'see' the photon as it makes ...
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2answers
357 views

Wave function interpretation $y(x,t) = (0.35m)\sin(10\pi t-3\pi x + \frac\pi{4})$

Wave function interpretation $y(x,t) = (0.35m)\sin(10\pi t-3\pi x + \frac\pi{4})$ I used to deal with function with one variable And now theres are two, how can I interpret them? Is $10\pi$ still ...
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101 views

EM Waves Energy Loss

Where does the energy go when two photons interfere destructively at a point on a screen in Young's double slit experiment ?
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Calculating phase difference of sound waves

An observer stands 3 m from speaker A and 5 m from speaker B. Both speakers, oscillating in phase, produce waves with a frequency of 250 Hz. The speed of sound in air is 340 m/s. What is the phase ...
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723 views

Phase shift of resonance [duplicate]

For resonance to occur, is it true that the force lags behind the motion by $\pi/2$? I saw some notes written that the motion lags behind the force by $\pi/2$ which makes no sense to me. As I watched ...
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313 views

Eddy current losses in electric steel by harmonics of a magnetic field

I am working on an model of a permanent magnet synchronous machine. Right now I am stuck with calculating the eddy current losses caused by the harmonics of the stator magnetic field in the electrical ...
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121 views

what is the difference between constant and changing magnetic and electric fields? How do they occur? How do they form an electromagnetic wave?

what is the difference between constant and changing magnetic and electric fields? How do they occur? How do they form an electromagnetic wave?
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How was the sinusoidal model for propagation developed?

It's a little difficult to explain this question .. but I'll try anyway. To the best of my knowledge propagation models - audio, RF - are modelled as travelling in a sinusoidal form. Surely if a ...
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352 views

Refraction and Reflection Seismology

So I am wondering if I got the difference right. Both methods use explosives to send waves into the earth's surface. Now reflection seismology tries to get information from the reflected waves; the ...
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1answer
259 views

Transmission of Gaussian Beam Through Graded-Index Slab

The $ABCD$ matrix of a glass graded-index slab with refractive index $n(y)=n_0(1-\frac{1}{2}\alpha^{2}y^{2})$ and length $d$ is $A=\cos(\alpha d)$, $B=\frac{1}{\alpha}\sin(\alpha d)$, $C=-\alpha ...
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324 views

Counting electromagnetic modes in a rectangular cavity and boundary conditions

The electric field in a cubical cavity of side length $L$ with perfectly conducting walls is $E_x = E_1 \cos(n_1 x \pi/L) \sin(n_2 y \pi/L) \sin(n_3 z \pi/L) \sin(\omega t)$ $E_y = E_2 \sin(n_1 x ...
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357 views

How do we find the frequency of wave propagated along the x-axis?

I don't know how to solve question like this: A transverse wave is propagated in a string stretched along the x-axis. The equation of the wave, in SI units, is given by:y = 0.006 cos π(46t - 12x). ...
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223 views

Rayleigh diffraction by circular aperture

I am a beginner to physics and would need an explanation on a statement in a book "Karttunen, Fundamental astronomy". In a section named "Rayleigh diffraction by circular aperture", author states: ...
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207 views

Behavior of shock waves at relativistic speeds

Suppose I am in a spaceship traveling inertially at a velocity $v$ that is of the same order as $c$. As I pass by a metal bar that is oriented parallel to $v$, someone hits it with another metal bar, ...
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613 views

Changing magnetic flux graph?

In regards to a graph of the changing magnetic flux in a generator such as this one: a) The equation of the graph should be $\Phi = BA \cos \theta$. As $\theta=\omega t$ (angular velocity*time), ...
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666 views

What makes waves at beaches to come with high velocity and frequency at nights?

When we are in beach we can see waves coming when the sun light goes of the waves amplitude will increase what is the reason Some people said me that for moon light the frequency and velocity of ...
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738 views

Wave diffraction explanation

I'm trying to understand wave diffraction and I found this wikipedia article. It's in Czech so I'll explain a bit. I'm interested in the 4 images I couldn't find on english wikipedia. The first one is ...
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261 views

Help me to visualize this wave equation in time, to which direction it moves?

The wave is $\bar{E} = E_{0} sin(\frac{2\pi z}{\lambda} + wt) \bar{i} + E_{0} cos(\frac{2 \pi z}{\lambda}+wt) \bar{j}$ Let's simplify with $z = 1$. Now the xy-axis is defined by parametrization ...
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How to calculate the intensity of interference multiple point in spherical wave? [closed]

Physics isn't my major T^T So, I'm going through a hard time to find the equation. I referenced this question. but It is calculating two different point sources which produce spherical waves with the ...
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What happens when a slow wave reaches lower hybrid resonance?

Lower hybrid resonance occurs when $n_{\perp}^2$ goes to infinity, and it occurs only for the slow wave solution, not the fast wave. Since $n_{\perp}$ is proportional to $k_{\perp}$, and $k = \frac{2 ...
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Why did we see intereference from a single point source?

In class we were doing an experiment where an agitator was used to create spherical waves on a ripple tank. I noticed that when using only a single paddle (so a single point source) that you could see ...
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2answers
37 views

What are the analogies between pitch and color? [closed]

I suppose there are some similarities to be made, what with sound vs light waves and I further suppose that lots of other people have thought of this before. When did these similarities (whatever they ...
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19 views

Relationship between frequency and amplitude of mechanical waves

Can two mechanical waves carry same energy whose frequencies are different?(assuming same medium but having different amplitudes
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18 views

Question on envelope-carrier description of traveling wave

I'm doing a research internship in attosecond physics right now, and one of the really important things in the field is the description of a propagating laser pulse as the combination of a slowly (or ...
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49 views

Double slit experiment with slit material acting as a detector

Suppose the classic experimental setup of the double slit experiment. What is the probability that an electron does not pass through the slits? That is, for every single electron that comes from ...
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1answer
30 views

Trouble understanding phase matching equation

consider a 2nd order non linear optical material, i.e. a material in which it holds that $ P = \epsilon_0 E + 2dE^2$. In the Born approximation, the non linear contribution to the polarization density ...
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24 views

Superimposed state vs. zero amplitude state

Two equal amplitude wave pulses approaching each other through some medium such as a string may form a region of zero amplitude when they overlap completely. At this point, the location of overlap is ...
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66 views

Questions related to resonance/standing-waves and sound

I understand resonance for a simple harmonic oscillator but not for more complex systems like standing waves. How can I be in resonance with the normal mode in an organ pipe? I understand that the ...
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25 views

Compute impulse response of a cavity for sound waves

Given a (closed or not) surface and a point emitting a spherical sound wave, how can I calculate the wave amplitude in any point of space, considering reflections on this surface ? The idea is to ...
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17 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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Transmission Line above infinite plane connected by impedance line - Is my drawing correct?

Okay, I was doing a question on transmission lines. The setup is a wire placed at distance $d$ above an infinite conducting plane. The impedance of such a line is $Z_0$. Then there is an impedance ...
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33 views

how does different colour wavelength intefere? [duplicate]

Say a red colour with 400nm mixes with blue colour with 700nm, but out of phase by a little. What would be the resultant colour? I would know how to represent the resulting wave mathematically, but ...
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33 views

Signal Induction in a Wire due to Alternating Current

I wanted to make sure I understand induction well enough. Assume we have two wires running parallel to each other. Wire A has a signal of $f(t)$, wire B has a signal of $\hat{f}(t)$. Let's connect a ...
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33 views

Standing sound waves phase difference

This is a basic question but I don't fully understand what is going on. When we have a pipe in resonance we get standing waves, where displacement antinodes are at pressure nodes and vise versa. So ...
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66 views

Reflection & Transmission curves of waveguides

I have simulated a grating-coupled waveguide in Comsol Multiphysics, the waveguide consists of 2 dielectric layers and air as the cover of waveguide. I have excited the modes of this structure by a ...
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25 views

Direct optical observation of the Arago spot: what would one see?

The Arago/Poisson spot is an excellent example of a constructive interference of diffracted light. In the traditional experimental layout, you observe projected light on the screen. The theory in this ...
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Cavity dynamics from traveling waves to standing waves

This is a question on mathematical physics. The conventional reasoning about the characteristic wave modes in a cavity is to apply the boundary conditions, namely, wave amplitude is equal to 0, and ...
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40 views

Instantaneous displacement of a traveling sine wave with an undisturbed starting condition

The equation for the instantaneous displacement of a traveling wave at time $t$, and at any position $x$ along the wave is: $$y(x,t) = A_{max}\sin(kx +\omega t + \phi)$$ But this is only valid ...
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Is light and sound waves interconvertible? [duplicate]

Light is produced when an air bubble underwater is collapsed with sound wave. Why does it happen so?
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Baker and Copson “The Mathematical Theory of Huygens Principle” 1987 page 17

In Baker and Copson "The Mathematical Theory of Huygens Principle" page 17, how is this equation derived (after the first paragraph): $ R_0 r sin(\theta) d\theta = R dR $ I don't even know where ...
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32 views

Drawing the wave function for a wave packet

I have the following infotmation: Amplitude-Function: $U(k) = Ae^{-a|k-k_0|}$ Wave Function: $u(x,t) = \frac{A}{\sqrt{2\pi}} \frac{2a}{(x-vt)^2+a^2}e^{ik_0(x-vt)}$ Uncertainty in x: $\Delta x = 1$ ...
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59 views

What can cause a change in wave's shape - One dimensional wave

what can cause a change in wave's shape of one dimensional wave moving through a rope? It's velocity ? or the wave's length ? What can cause him change his shape.
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Spring Constant - Waves

I tried to prove that for the same length of spring , a one dimensional wave that moves faster in spring 2 than spring 1, its spring constant will be lower than the spring constant of spring 1. ...
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Can the motion of a cracking whip be described as the interference of two waves?

I was watching a whip crack in slow motion and I noticed that the motion of the whip could be described using two different circular descriptions. 1) the user circles the whip around over his head, ...
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64 views

group and phase velocity of free particle [duplicate]

If Schrödinger wave equation is for matter waves then for a free particle Group velocity $V_g =2$ Phase velocity $V_p$ But matter waves satisfy the relation $V_g V_p = C^2$ where $V_p>C$ Does this ...