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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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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50 views

Woodwind instruments overtones [duplicate]

When playing woodwind instruments, e.g., flute, if one blows harder, the sound will be one octave higher. Even harder gives even higher overtones. Does anyone know why?
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Where does wave frequency come from

I am trying to wrap my head around where do oscillations in electromagnetic waves come from. As an example if I would take a string of guitar and ring it, it would produce a certain sound based on the ...
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1answer
65 views

Single slit diffraction pattern in 2D

I was looking at previous exams and I saw a question with single slit diffraction. Please look at picture on the website: http://www.physicsforums.com/showthread.php?p=4807732#post4807732 So, this ...
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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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3answers
106 views

It seems that the harmonic (integer multiple) overtones of a sound usually all have the same phase. Is this true, and if so why?

And if you were to give each of them different phases, would the sound start to sound "off", or would it sound the same? All the same frequencies would be present, which makes me think it might sound ...
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40 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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2answers
62 views

Sea surfer position displacement

Waves are means by which the energy propagates through a medium (e.g., sea water). This is not associated with a net movement of water in the direction of wave propagation. If this is the case, then ...
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50 views

Intuitively proof that intensity of a wave is proportional to the square of its amplitude [duplicate]

Firstly I would like to know if this is valid for every kind of wave, or are there any conditions/exceptions where this is not valid. But the main question is, is it possible to prove this fact for a ...
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1answer
122 views

Why does a minor vertical vibration cause my coffee to spill?

When I walk my kid sometimes I put a cut of coffee in a cupholder attached to the stroller. When I push the stroller over a brick pavement it seems to vibrate vertically. That is enough for the coffee ...
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69 views

Sound Wave out of phase

I connected my speakers to my sound system switching the +ve and -ve one of the speakers I can notice them beating out of phase but how come I don't hear any difference and at what position will it ...
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3answers
68 views

Unpolarized Light

Suppose I had a ray of unpolarized light, and I was sitting inside the beam and looking at the electric fields oscillating, then , if I am looking at a point how would the oscillations look like? I ...
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1answer
71 views

Total internal reflection and waveguides

I'm looking at a model of a planar dielectric waveguide along the lines of this picture: For the wave inside the $n_1$ dielectric slab to totally internally reflect $\theta_M$ needs to be smaller ...
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1answer
50 views

Resonant Frequency & Opera Singers [closed]

Would it be possible under math of strings to note the frequency of each string vibrations? And in doing so, in hand with using the technique opera singers use to shatter glass with their voice, would ...
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2answers
90 views

Interpretation of dispersion relation

In my research, I found that my system has the following dissipation relation: $$\omega^2=k^2+k_0^2\ , $$ where $k_0^{-1}$ is an intrinsic lengthscale of the system and the units are chosen so that ...
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2answers
61 views

Standing sound wave in a wind instrument

So I've had this question bugging me ever since I saw sound at physics class: How is it possible to match the resonance frequency of a column of air in an organ pipe and form a standing sound wave by ...
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1k views

Why does wavelength affect diffraction?

I have seen many questions of this type but I could nowhere find the answer to "why". I know this is a phenomenon which has been seen and discovered and we know it happens and how it happens. But my ...
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0answers
39 views

How is the imaginary part of angular frequency omega related to the imaginary part of the refractive index?

I'm trying to find the attenuation constant (leak rate) $\alpha$ from the imaginary part of the refractive index of a lossy material. I have the eigen frequency $\omega$ for my structure which has an ...
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2answers
45 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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1answer
36 views

What length should be the gap to block UV waves from the Sun?

The origin of the question is practical, but the theoretical part is interesting too. Let's rest a little bit on the roof on a sunny summer day. We don't want to get burned, so we usually place some ...
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1answer
191 views

Compression vs Rarefaction in Sound Waves

I am currently looking into solutions for Sound Classification, and I came across Ludvigsen's methodology (if anyone wishes to refer to it). The problem is that a sample graph of amplitudes in one of ...
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1answer
120 views

Plane wave complex notation

As far as I know, the function: $$ \vec{E}(\vec{r},t)=\vec{E_0}\cdot e^{i(\vec{k}\cdot \vec{r}-\omega t)} \hspace{2cm}(1) $$ is a mathematical solution of the wave equation: $$ \nabla^2 ...
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1answer
32 views

Nuclear explosion wavelength data

I am looking for data source (or chart) of spectral data that is being emitted on detonation of nuclear or thermonuclear explosion. Reason I am looking is to see if this data has specific signature ...
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211 views

Relationship between the continuity equation and the wave equation

What exactly is the relationship between the continuity equation and the wave equation? Suppose $J^\mu$ is a contravariant vector that satisfies the continuity equation $\partial_\mu J^\mu=0$. Let ...
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1answer
43 views

Would half of electromagnetic wave be absorbed on first sensor?

If I would set up electromagnetic emitter that would emit one wave, but while it would be emitting it I would spin emitter 180 degrees at such speed that one half of wave would be emitted in that time ...
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1answer
80 views

How can such a wave exist at the surface of the sun?

Recently, I came across the following picture from NASA's SOHO observatory: It seems evident that this is a transverse wave (mind the ring which is bright and dark). But how can this be the case ...
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1answer
209 views

Why do waves occur?

I've seen a couple derivations of wave equations, but I was never convinced that waves would actually exist. Consider a spring with a compression pulse in a part of it (that is, assume it has an ...
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1answer
41 views

Time dependency of the phase of a single photon

I am wondering if a wave packet of a single photon in the time domaine $$ \psi(t)=|\psi(t)|\; \text e^{\text i \varphi(t)} $$ can have a different $t$ dependence in phase than the simple phase ...
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93 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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1answer
31 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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1answer
42 views

(air pressure and displacement) Isn't this image wrong?

Isn't this figure wrong? P(x,t) = -B(dy/dx) . If the derivative of air displacement has a maximum, then this is where the pressure is minimum, not maximum as this figure suggests. Could someone ...
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4answers
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Can I compute the mass of a coin based on the sound of its fall?

Other day, I bumped my bookshelf and a coin fell down. This gave me an idea. Is it possible to compute the mass of a coin, based on the sound emitted when it falls? I think that there should be a ...
2
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1answer
55 views

Standing wave velocity

My question is simple: How is it that a standing wave has velocity? I mean, it's not travelling... A lot of equations depend on this concept, for example: $f_n = \frac{nv}{2L}$ Here we're ...
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1answer
26 views

How to measure area under the waveform (electric current)?

I have a current waveform from my circuit which goes up and down the x-axis. x-axis represents time and my y axis represents current. How should I calculate total area under the curve? Should I take ...
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1answer
85 views

What really is a wave and how it is treated mathematically?

First of all, I know there's a much alike question here but this is not duplicate since I couldn't find there the answer I'm seeking. My problem is the following: I know that intuitively we have a ...
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43 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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1answer
528 views

What determines the speed of waves in water?

While I was walking my dog this morning, I passed over a canal filled with boats, barges, and kayaks all of different masses and moving at different speeds. I noticed that all of these vessels left ...
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1answer
66 views

What can make signal triangulation tricky?

Usually, when you're trying to find a source of whatever signal, you move around the source and then calculate the position using triangulation. I'm specifically talking about low frequency signals, ...
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130 views

What is the theoretical/intutive meaning of $x(t) = x_0 \cos ( \omega t + f )$?

What is the meaning of $x(t)=x_0 \cos(\omega t+f)$, where $x_0$ is the amplitude, $\omega$ the angular frequency, $t$ time and $f$ the phase constant? I know how to solve the mathematical problems ...
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Is there a second order differential wave equation that only allows a finite set of discrete eigenvalues?

I tried constructing a second order differential wave equation that only allows a finite set of discrete eigenvalues by using the power series expansion such as \begin{align} A_{j+2} = ...
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33 views

To find the center of charge in current waveform

I have a circuit for which output current waveform has both positive and negative points. Now I want to get a center of the charge for this waveform (means where my net charge is concentrated ?). Is ...
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1answer
33 views

Does an electomagnetic field “modulate” an electric field?

Lets imagine an electromagnetic wave is vertically polarized. If you ignore the magnetic component, the electric field lines would point upwards from the ground or downwards in a cyclical way and of ...
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20 views

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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1answer
68 views

Wireless electricity through Wi-Fi power signal?

Could there be a method to obtain and send worldwide electricity through WiFi? I mean if we have internet everywhere and only need a WiFi device, can we apply the same to electricity technology? or ...
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2answers
43 views

What is being deprived when a photon is being watched in double slit experiment?

How are photons being watched in the double slit experiment? What exactly does being observed mean, as it is obviously changes the state of the photon somehow - it must be depriving the photon of ...
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99 views

can silence happens when 2 sound waves destroy each other [duplicate]

Hi is there any possibility that you located between 2 sound sources and u hear nothing? as we know 2 wave in opposite direction will destroy each other...
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1answer
70 views

Finding speed of light by $c=f\lambda$?

When considering EM radiation as waves it is said that it is electric and magnetic fields that oscillate with time. Therefore $f$ is not frequency of distance but of electromagnetic fields. I have ...
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1answer
127 views

Wave Packet in Curved Spacetime

It is known that the classical equation of motion for a scalar field wave packet on a curved spacetime background gives the geodesic trajectory (the e.o.m. is $(\nabla_\mu \nabla^\mu + m^2) \Phi=0$). ...
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60 views

Transmission of waves

How do you know if a wave will transmit when it hits a media boundary? Will a portion of the wave always be transmitted when a wave hits a media boundary? My textbook says part of the wave will be ...
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102 views

A strange audio phenomenon, could there be a physical interpretation to it?

http://mathoverflow.net/q/165038/14414 Motivation : Here is a motivation as to why this problem is so important. Let $f(t)$ be an audio signal. We can safely asume it to be bandlimited to 0-20kHz as ...