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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Energy Proportional to the Square of the Amplitude

I don't understand how the energy of a wave is proportional to its amplitude squared...For example, if we consider simple harmonic motion at the maximum displacement, there is no kinetic energy and ...
8
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2answers
229 views

Would fog impair echolocation abilities?

I was driving down a major highway today and the fog was thick enough I could barely see 40 ft in front of me. I then wondered if I had had some other form of perception could I have perceived my ...
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6answers
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Do the electric and magnetic components of an electromagnetic wave really generate each other?

Frequently when EM waves are taught, it is said that the change in electric field causes a change in the magnetic field, which then causes a change in the electric field, and so on and so forth. But ...
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1answer
485 views

Wave superposition, is my textbook wrong?

Here's the question: Two coherent electromagnetic waves are incident simultaneously at some point in space. The intensity of each independent wave is $I_0$. What is the intensity of the superposition ...
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0answers
41 views

How do I find the spatial modes on a circle? [on hold]

Hello, I have a wave on a circular rope and I have to find solution like $$u(t,\theta )= U(\theta )e^{iwt}$$ With the wave equation I find : $$U(\theta )=acos(\frac{w\theta }{c})+bsin(\frac{w\theta ...
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27 views

Tethered vs Liquid membrane [on hold]

Can anyone answer me what is a difference between an LIQUID MEMBRANE and a TETHERED MEMBRANE. I read a lot about it in different textbook, but it seems that I cannot pinpoint the exact difference. ...
-4
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1answer
53 views

Light - What is it? [on hold]

First of all, please excuse my bad english. I am from Germany. I am interested in, what light really is. I know, there is a range in the spectrum, and this range is visible. This is defined as light. ...
2
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1answer
68 views

Light follows the shortest path, but to where?

I'm a high school student and I'm trying to understand why waves bend when they refract. I read a few answers on the site, and the explanation that they follow the shortest path makes sense enough to ...
2
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1answer
33 views

Unsmooth behavior of water waves

I happened to come across this rather interesting picture of a very deformed (or perhaps intricate) wave. The structure looks like it illustrates a superposition of multiple waveforms, as intuitively ...
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1answer
31 views

Question about group velocity and travelling waves

I'm trying to learn some basic quantum mechanics and I have a question related to group velocity of a travelling wave. I know there are already a few questions related to group velocity, but I ...
0
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0answers
28 views

Signal decompositon [closed]

I am not a good in writing algorithm but please follow below steps 1.There are 4 1D periodic signals.3 of them are given by \begin{cases} x(t)=4\sin(10\pi t) \\ y(t)=8\cos(20\pi t) \\ ...
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1answer
39 views

can we calculate length and direction of radio waves that how far radio waves are coming and from which direction…?plz tell if anyone know [closed]

I am asking this for programming purpose.suppose one person calling me by cellphone and i want to measure that how far this caller from me and from which direction.to do so i am asking this question.i ...
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1answer
24 views

Disparity between two texts on intensity and phase interference - which is right?

So, I'm learning phase interference. Imagine we have two waves. $$ E_1 = A_0sin(wt) $$ and $$ E_2 = A_0sin(wt+\phi) $$ With $$ \phi = \frac{2\pi}{\lambda}dsin(\theta) $$ Which is the path ...
4
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1answer
52 views

Speed of sound in an inifinitely dense medium

Curious thought i just had. The speed of sound is affected by a few factors, but the density plays a large role. As density increases, does this mean that sound could approach the speed of light? If ...
0
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1answer
37 views

How to derive path difference ($\Delta l=d\sin \theta$) for double-slit interference?

The Wikipedia page for the double-slit wave interference experiment states that the path difference between waves diffracting from the two slits is equal to: $$ \Delta l=d\sin \theta $$ where $d$ is ...
3
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1answer
51 views

Does Fermat's principle of least time apply to sound waves?

I am reading Feynman's presentation of Fermat's Principle of Least Time, which explains the behavior of light; does it apply to waves in general? for example sound waves or waves on the surface of ...
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0answers
25 views

Generalized long wave and KdV equation

I have read many papers about benjamin-bona-mahony (BBM) equation or Regularized Long Wave (RLW) equation and found that BBM equation can be derived from KdV equation. from other papers i got others ...
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1answer
61 views

Have we really measured the wavelength of light? [duplicate]

Have we practically measured the distances between the variations of electromagnetic radiations in space in nanometers or is it just theoritical because of calculations? Also the one who have marked ...
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2answers
35 views

Does the velocity of a wave change after being reflected against a moving object? [closed]

This problem is from my friend ; A man is waiting for a bus. The bus is heading toward him with $v=20\dfrac{km}{h}$ To evaluate the duration, the man sent a wave with $f=880Hz$ toward the bus. ...
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3answers
43 views

General solution to the wave equation proving dependence on $x \pm vt$

I am trying to solve for a general solution to the wave function and demonstrate any solution has the form $f(x,t) = f_L (x+vt) + f_R (x-vt)$ I have used separation of variables f(x,t)=X(x)T(t) to ...
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0answers
46 views

How does light manage to change its course at the boundary of two media of different optical densities?

This is a conceptual question. I already know the law of refraction but I need something like an idea of the Physical process from both particle and wave theory standpoints. Why does a ray of light ...
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0answers
23 views

Functions of the form $F(x-ct)$ written as superposition?

In this section of the Wikipedia article on the wave equation they do the following: $$\int^{\infty}_{-\infty}s_+(\omega)e^{-i(kx+\omega t)}d\omega +\int^{\infty}_{-\infty}s_-(\omega)e^{i(kx-\omega ...
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1answer
56 views

The general equation for a wave packet derivation? [closed]

On Wikipedia it gives the general equation for a wave packet (and therefore for a wave?) to be: $$u(x,t)=\frac{1}{\sqrt{2\pi}}\int^{\infty}_{-\infty}A(k)e^{i(kx-\omega t)} dk$$ I have been trying to ...
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0answers
10 views

Wave velocity (R)LC circuits.

I'm attempting to simulate some fluid like mechanics using circuits. Specifically wave propagation. I am attempting to measure the wave propagation velocity using an oscilloscope on the circuit below, ...
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1answer
34 views

Is a rope wave a perfectly transverse wave?

When i create a disturbance in a rope.What is happening at the particle level.I imagine the particles and the forces on the particles like this: According to my model there should be some ...
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3answers
55 views

Why is wave a function of volts?

I'm looking at a beginner's book on Fourier and waves, and the very first graph shows a periodic wave where the horizontal axis is time (msec) and the vertical axis is something noted as "MAG(V)" ...
3
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1answer
26 views

Wave interference on window film coating

"The windows in an office tower are coated with a film to minimize reflected light of wavelength 550 nm. If the glass has an index of refraction of 1.52 and the film coating has an index of refraction ...
2
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1answer
31 views

Patterns in laminar flow of tap water

This is a simple experiment that anyone can do at home. Open your tap so that the water maintains a laminar flow, and the cross section of flow is considerably thin. Place your finger 3-4 cm below the ...
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2answers
68 views

What is the significance of angular frequency $\omega$ with regards to wave functions?

What is the physical significance of $\omega$ in a function like $$ f(x) = Asin(kx + \omega t) $$ The only place that I am familiar with angular frequency is when dealing with circular motion, but ...
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1answer
34 views

Fourier series for a wave on an infinite string?

From "Vibrations and Waves" by A.P. French I know that any wave on a string length $L$ can be represented by: $$y(x,t)=\Sigma^\infty_0 A_n \sin(\frac{n\pi x}{L})\cos(\omega_nt-\delta_n)$$ But can we ...
0
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2answers
70 views

Are matter waves (de Broglie) classified as transverse or longitudinal? [duplicate]

We know that waves are of two types: transverse and longitudinal, and we have studied about de Broglie waves as well, so which one of them is it? Or we have other means to classify them?
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1answer
46 views

What is slinky-approximation?

I was reading the derivation of wave-equation from Berkeley Physics - Waves by Frank S. Crawford Jr. Let $\Delta z$ be a small segment of a continuous string . At equilibrium, tension is $T_0$ at ...
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3answers
94 views

What makes waves propagate?

Why do electromagnetic waves propagate? I have searched a lot about EM waves, but I am still unable to understand what is driving them. Could you explain?
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2answers
55 views

Singing for physicists: How to resonate by body cavities with my voice?

My body has various cavities, such as my throat, mouth, chest, and nose. This cavities have resonant frequencies. I also have a voice box, which creates sound. How do I create sounds at the resonant ...
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2answers
82 views

Explain how waves have momentum?

A question on a practice test I'm taking is as follows: By shaking one end of a stretched string, a single pulse is generated. The traveling pulse carries: A. mass B. energy C. momentum D. ...
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1answer
39 views

Question regarding charge and acceleration

From a stationary charge electrostatic fields arise. From a moving charge, magnetostatic fields arise. From an accelerating charge, EM waves arise. So i wonder -- what about a non-constantly ...
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45 views

Direct interaction theory

I got to know about a kind of theory or formulation of EM which doesn't have the idea of fields in it. In that theory I guess field isn't that which mediates the force between two charged particles. ...
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1answer
35 views

Sound waves and chromism?

I am definitely not a physicist, but I have a question related to Physics so I thought I'd give it a try. Please excuse my ignorance. :) I am somewhat familiar with the changes in color caused by ...
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0answers
15 views

Phase change by reflection [duplicate]

Let's consider a light ray falling on a cuboid made of glass at the angle $\alpha$. Then there will be a reflected ray $A$. The ray will also refract. Let the refracted ray be $B$. Ray $B$ will be ...
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1answer
29 views

In a noiseless environment, how accurate do today's transmitters send EM waves?

Suppose that there is no external noise in the environment. How accurate are today's TEM wave transmitters in such a case? So if we want to send $200\cos(1000\pi t)$, can transmitters send exactly ...
1
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0answers
40 views

The interaction between waves and particles according to their wavelength [duplicate]

Why do EM waves with a large wavelength like those in the red range (and radio waves) interact with particles less than those in the blue range? That is the reason why the sky is blue, is that right? ...
1
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1answer
31 views

Is it possible to “pull” sound waves using only an object?

Say, for instance, I am outside standing 20 feet away from a speaker. Is there an object I can put on my body that would allow me to feel the bass of the music more, without picking up the vibrations ...
0
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1answer
26 views

Reflection of Sound wave (Pressure Wave)

I want to study about the phenomenon of reflection of pressure waves as in an open ended organ pipe. Please suggest a suitable resource? I know about the harmonics in a stretched string and I can use ...
1
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0answers
24 views

How can we detect the property of matter by using mechanical waves or IR or any other way

First of all, I am in high school[to tell that I don't know much physics]. And the second thing is that, I am not sure whether this question is specifically related to physics. What I want to ...
6
votes
2answers
757 views

What should be the intuitive explanation of wave equation?

$$\dfrac {\partial^2 y}{{\partial x}^2} = \dfrac{1}{v^2} \dfrac{\partial^2 y}{{\partial t}^2}$$ is the wave equation in one dimension. But what should be the intuition behind it? That is, what meaning ...
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0answers
28 views

How fast does the force of pulling a straight rope propagate along the rope? [duplicate]

Is it instantaneous or does it somehow propagate like a wave along the particles of the rope ?
2
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1answer
42 views

How does energy get transfered from destructive interference point to constructive one?

If there are two pressure waves (like sound waves) that travel in opposite directions and have the same amplitude then destructive interference occurs: one wave will compress the air particle (here ...
3
votes
3answers
104 views

Why is there a negative sign in front of the optical wave?

In undergrad I lost (a lot) of marks in my optics class for writing: $$A(t) = \exp(i(\omega t + \phi))$$ Instead of: $$A(t) = \exp(i(-\omega t + \phi))$$ In a derivation where I must have needed ...
4
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1answer
37 views

Interference and windows

The other day i was learning about interference patterns with the effect of a bubble making a rainbow on the surface. I learned that the reflections from both sides of the soap can interfere ...
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21 views

What have we built? A resonant loop antenna? Rhombic?

Some background, my partner and I have built an antenna we are supposed to characterize for an assignment, and compare it to physical predictions. However, we don't know what type of antenna we have ...