Waves Definition and 1000 Threads

It's been stated that the index of refraction of materials varies with frequency throughout the EM spectrum. What are the index of refraction for various materials in the radio frequency?

If we imagine launching an electron wave in a reference frame S with speed v, should someone viewing the electron from frame S1, which is in inertial motion referring to S, use the relativistic velocity addition to calculate the speed of the electron?

So, is water for water waves, what is the vacuum for EM waves traveling in vacuum. I know the analogy can't be exactly perfect because water molecules oscillate in the presence of water waves, but in vacuum nothing seems to oscillate? Or the vacuum oscillates in some way? And no I am not trying...

Hello ! As we know by definition that: "Constructive interference occurs when the phase difference between the waves is an even multiple of π (180°), whereas destructive interference occurs when the difference is an odd multiple of π." But my question is in the case of destructive...

In this paper in NASA https://www.giss.nasa.gov/staff/mmishchenko/publications/2004_kluwer_mishchenko.pdf it claims (at page 38) that the defined spherical waves (12.4,12.5) are solutions of Maxwell's equations in the limit ##kr\to\infty##. I tried to work out the divergence and curl of...

This is my first post so I apologize if i am in error anywhere. I recently had a thought that I have had trouble confirming. Based on the following assumptions. 1.) As you accelerate an object near the speed of light it’s mass increases exponentially. 2.) Mass warps space time. 3.) Spacetime...

in a nutshell what are the differences between gravitational and electromagnetic waves?

Hello I'm new to this forum and interested in astrophysics and metaphysics. My first question here is if we can create nano sized wormholes to send information faster than light to other stars for example. We don't need to travel if we could send small satellites or even just radiowaves to the...

I was studying radiation and came across an article: https://www.wtamu.edu/~cbaird/sq/2014/04/01/light-has-no-mass-so-it-also-has-no-energy-according-to-einstein-but-how-can-sunlight-warm-the-earth-without-energy/#:~:text=In summary, all objects with,not the only massless object. Which said...

Hello, I'm considering the "beats" phenomena. I have two plane waves in some medium with a refractive index n(ω), one propagates in a z direction and second in a direction making an angle θ with z axis. Waves have frequencies ω1, ω2 (not necessarily equal) and k-vectors k1, k2 (not necessarily...

Hello, This article caught my attention recently and I have several questions on the subject that I'd like to get opinions on. Before going further, I realize a technical discussion is way past the "I" tags range. Please adjust as necessary and thank you in advance. My attention was originally...

I am getting confused by this question. Nevertheless, I tried answering this question. When I see the word pulse, it brings to my mind a pulse traveling in a rope as shown in diagram below and I cannot relate dispersion to the rope medium in which pulse is travelling. What I do know is that...

I read in a book that high frequency electromagnetic waves are more able to penetrate than low ones , so why radio waves can penetrate walls when light cannot?

Are gravitational waves purely temporal? An object with no spatial velocity experiences gravity due to temporal velocity?

Using the equations mentioned under this question, I came up with following analysis and directions of velocities on either side of ##x_1##. Also, I'm not sure if there is an easier qualitative way to know the velocity directions rather than do a detailed Calculus based analysis?

I know that standing waves form in an open organ pipe. Since, standing waves can only form from superposition of original wave and reflected wave, so there must be a reflected wave in an open organ pipe. But I fail to understand how sound wave can reflect at the open end of organ pipe.

To me, they all look incorrect. Oh hang on. Ultrasonic waves. I misread that. It's no 6 then.

The second diagram is my attempt at the solution, in which the dotted part is the pulse in the rope a very small interval of time after ##t=0##. Point A should be at rest since we know wave is moving towards right and point A on the rope becomes a part of initial horizontal part of the string a...

Recently viewed video about wormholes that required negative energy to create it. Suppose hypothetical aliens have discovered this technology. Spaceship enters in first point and exit at second. To prevent spaceship destruction they might have technology to smooth gravitational waves on exit...

Hello, this is a repost from a much less-clear question I posted before (link to question: https://www.physicsforums.com/threads/triangles-inside-a-circle-to-represent-raypaths-inside-an-ideal-earth.1011998/#post-6596165). It's kind of a loaded question, however it can be expressed as triangles...

Hello Guys! I'm studying radio waves and I can't understand the following: Radio waves propagates through Earths surface as a ground waves, line-of-sight waves or skywaves. There is a phenomenon that occurs with line-of-sight waves (and maybe with ground waves?) known as height gain, in which...

Waves are energy moving. Light is moving packets of fixed amounts of energy. Why must we invoke particles to understand light? How is a wave (energy moving) antithetical to packets of energy?

I really cannot ask this question well. I can only hope its not simply a waste of the readers time. I won't finish every sentance with "maybe I'm wrong", just assume its in my mind every time I hit the period key. An electron on a screen leaves a pixel spot, this pixel spot is a measurement...

Electromagnetic or gravitational wave carries energy and momentum from place to place as,I understand.Does it imply that such waves only can carry information and if their energy gets dissipated as heat, the information contained is lost. Is this information content is to be decoded by human...

in classical physics, when a charged particle oscillates, it emits an electromagnetic wave, and the frequency of the wave depends on the frequency with which the particle oscillates. But in quantum physics, when an excited atom emits a photon, the energy of the photon depends on the magnitude of...

We assume incident waves to be: y(1)=y(o)sin(wt) y(2)=3y(o)sin(wt+Φ) As Intensity~(Amplitude)^2 We get y(2)=3y(1) This gives us I(2)=9I(1) We assume I(1)=I(o) & I(2)=9I(o) Resultant Wave Intensity I=I(1)+I(2) +2√(I(1)*I(2))*cosΦ ----> I(o) + 9I(o) + 6I(o)cosΦ (We can take cos of this...

During our classes, we haven't discussed the situation of a tube closed at both ends. But, assuming the position of the nodes and antinodes, I think it's a case similar to the one where the tube is open at both ends, so I think that f = v/λ = nv/(2L). Using the numeric data, my frequency would...

I've always had difficulty grasping why the electric and magnetic fields are in phase in EM waves in a vacuum. Of course, Maxwell's Equations imply that is the case, but I had a hard time intuitively visualizing it. Then I found this short video on YouTube. I would appreciate your opinion...

Treating water as having a conductivity of ##\sigma \sim 5 \ \mathrm{Sm^{-1}} \gg \omega \epsilon_0 \epsilon_{\mathrm{r}}## then Maxwell ##\mathrm{III}## implies\begin{align*} \nabla \times \mathbf{H} = \sigma \mathbf{E} + \epsilon_0 \epsilon_{\mathrm{r}} \dot{\mathbf{E}} = -i \omega \epsilon_0...

The classical free surface profile for the solitary wave for irrotational and incompressible fluids for small amplitude and long wavelength is the classical Korteweg-deVries(KdV) equation given by:\frac{\partial\eta}{\partial t}+\frac{\partial \eta}{\partial x}+\eta\frac{\partial\eta}{\partial...

An exact gravitational plane wave solution to Einstein's field equation has the line metric $$\mathrm{d}s^2=-2\mathrm{d}u\mathrm{d}v+a^2(u)\mathrm{d}^2x+b^2(u)\mathrm{d}^2y.$$ I have calculated the non-vanishing Christoffel symbols and Ricci curvature components and used the vacuum Einstein...

In this case, the waves are sound waves and radio waves. On Saturday, I drove up to Asheville NC for some sightseeing. Although I've been to stamp and model-train shows south of town nearby many times, I had never done any real sightseeing downtown, only driven through it. Stop 1 My main...

I'm reading about excitation of surface plasmons, and there's a claim in the derivation I don't know how to prove. The geometry is two infinite slabs of material with negligible permeability (##\mu_1 = \mu_2 = 1##) and different permittivity ##(\epsilon_1 \neq \epsilon_2 \neq 1)##. The claim...

Do wavefunctions collapse when looked at? Or does observe mean something else? https://www.nature.com/articles/d41586-018-05892-6 This article is where my information is from, physicists talking about how our mind causes the collapse.

Why are gravitational waves able to move at the speed of light?

It seems to me that gravitational waves are ignored when inflationary physics are described. I'm not very well read, and honestly do not know so much about most of the physics going on with inflation. Still, wave mechanics matter, harmonics matter, and it just seems intuitive to me that in order...

Are there soundwaves so tightly packed that you could have two people standing next to one another and fire sound at a distance directly into one person's ear as that only that person hears it?

##-w1## and ##-w2## are to shift the cosine graph to the right, and ##\frac{2pi}{\lambda}## is to stretch the graph. But I can't seem to draw an appropriate ##y1+y2## graph (quite irregular) and I struggle to find the resultant frequency and wavelength. Also, why is there angular frequency in a...

Hello (Perhaps this should be in physics, but perhaps it should be mechanical engineering (fluid mechanics). I attach a picture of water running down the street near my house. The street is a nearly constant 15 degree incline that goes on for about 1 kilo-meter with no speed bumps. The...

The question is to explain the equation of motion of the red ball. The string is massless and a small ball of mass m is attached to the string halfway. I just assumed the mass of the string is the same as the mass of the ball and explained the equation A cos(Wt) by defining the terms. I'm not...

Hi! So I'm trying to understand electromagnetic waves but I encountered different definitions: one in terms of electrons and one in terms of photons. Which ones are actually used to produce electromagnetic waves and how? Also, I saw that alternating current generates electro magnetic waves, but...

The elementary treatments I've seen show the shock wave spreading out in spheres centered on the plane and growing in radius at the speed of sound. So, clearly, the shock wave is sound, but what sound? What is it the sound of? In order for the plane to give off sound, it has to be making a...

Let a spherical wave propagate from the origin, $y = ADcos(wt-2\pi r/ \lambda)/r$. Also, let a plane wave propagate parallel to the x axis, $y = Acos(wt-2\pi r/ \lambda)$. At x = D there is a flat screen perpendicular to the x axis. Find the interference at the point y on the screen as function...

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How do gravitational waves in spacetime stretch and compress solid matter such as the LIGO experiment. I ask this because the expansion of spacetime of the Universe doesn't seem to have any effect on the small scale ie the solar system.

Hi ! It catches my attention that atomic particles such as protons, neutornes, electrons and their respective subparticles such as Quarks are theoretically formed by high-energy electromagnetic fields such as gamma rays and then the gravitational field that would generate the mass of these...

Hi, I would like to ask for some clarification about the physics involved in the gravitational waves detection using interferometers. Starting from this thread Light speed and the LIGO experiment I'm aware of the two ends of an arm of the interferometer (e.g. LIGO) can be taken as the...

So I've kind of made the assumption that there will be an odd number of plane waves and the same amount above and below the z-axis. Then, using the diagram below, I determined the angle the nth plane wave makes with respect to the z-axis to be the angle it makes with respect to the n =1 plane...

A popular theory is that black holes gradually leak information because of black hole evaporation due to hawking radiation. When black holes merge, a significant portion of their mass is converted into gravitational waves. If it's true that black holes leak information due to hawking radiation...

Asin(wt)}+Bsin(wt+a) Asin(wt) +B sin(wt)cos(a) +Bcos(wt)sin(a) Asin(wt) + ksin(wt) + Lcos( wt) (A+K) sin(wt) + Lcos(wt) Fsin(wt) + Lcos(wt)