Wave Definition and 999 Threads

Let’s suppose we have an electron with a Gaussian eigenstate, as the time runs, the wave spreads in space without changing its energy, however, the induced EM field caused by the particle decreases its energy. I assert this from the classical electromagnetism result in which the more...

Homework Statement http://cafeptthumb2.phinf.naver.net/MjAxNzAzMTVfMjcw/MDAxNDg5NTY5MTEwOTk5.FfccOAaDqBZbb9wXwuUWda8EN1aVvzMdcXO0GvaWwTsg.EjdATfmPtj-DteqAXFu9urHMslV8JTeridwC4ZNoJ68g.PNG.nikel92/asfasf.PNG?type=w740 Homework EquationsThe Attempt at a Solution...

I'm studying Quantum Field Theory and the first example being given in the textbook is the massless Klein Gordon field whose equation is just the wave equation \Box \ \phi = 0. The only problem is that I'm not being able to get the same solution as the book. In the book the author states that...

I was thaught you can create a sinusoidal wave by making a source oscillate with simple harmonic motion in a medium, such as moving one end of a rope up and down to create a periodic transverse wave. For transverse waves, it is easy to see that every particle in the rope moves up and down with...

Hi I was told by physics lecturer that both the wave speed and wave length of light changes when it enters a medium, however I questioned this stating that if both wave speed and wave length changed then frequency must also according to the formula c = fλ. He stated that "frequency is energy...

I'm trying to get my head around some ideas in Quantum Mechanics, but I'm trying to find a visual/mental image of the ideas, so that I may, in some cases, understand a little better, if that's even possible. I have a mental image of wave/particle duality and I'd like to know if it's a valid...

Hi, Physics forum! Just a little push of my doubts I hope somebody could help me with my confusion of one of our home works. I know that all boundary conditions are zero. My doubt is how do I interpret (x,y,0)=0.01 source in the figure? Where is it located in the grid. I am hoping someone...

What exactly do you mean by observing a state/ collapsing wave function. What is observing? Is it seeing the particle? Hearing? Also how cautious do you have to be near a quantum computer so that you don't collapse its wave function?

Homework Statement A speaker blares out music with a power of 10 W. Assuming the air has a temperature of 50°F and a pressure of 1 atm, what is the sound intensity level in decibels at a distance of 100m away? What is the maximum pressure variation at that point? What is the distance at which...

Homework Statement Find the group velocity for a shallow water wave: ##\nu = \sqrt{\frac{2\pi\gamma}{\rho\lambda^3}}## Homework Equations Phase velocity: ##v_p = \nu\lambda## group velocity: ##v_g = \frac{d\omega}{dk}## ##k=\frac{2\pi}{\lambda}## ##\omega = 2\pi \nu##The Attempt at a Solution...

Homework Statement Homework Equations The right hand section (A) has an incident and reflected wave $$y_1=Ae^{i(kx+\omega t)} +A'e^{i(-kx+\omega t)} $$ The middle section (B) has a transmission reflected wave $$y_2=Be^{i(k_2x+\omega t)} +B'e^{i(-k_2x+\omega t)}$$ Section (C) just has the...

Hello, at the moment, I am working on my project of particle acoustic levitation, but I want to move the particles in a certain direction. In order to generate ultrasound wave for moving a particle, I want to use two transducers. Now, my question is: Has the reflection of those sound waves...

If we take the Lagrangian of a spin-0 scalar field and use the Euler-Lagrange equation, we end up with the Klein-Gordon equation. Does that mean that the wave equation of spin-0 scalar particles is the Klein-Gordon equation?Thank you

Homework Statement I post here to check if I am in the right way to understand this point in the book. The wave function of free particle is ##Ae^{\frac{i}{\hbar}(px-Et)}##.This could be regarded as ##{\phi}(x,t)=Ae^{\frac{i}{\hbar}S(x,t)}##. ##S(x,t)## is the free particle's least action...

It is well known that wave particle duality was also observed with large particles up to 10000 amu: Abstract of Paper : https://arxiv.org/abs/1310.8343 Doesn't that make pilot wave theory a more logical interpretation? For example it is easier than the whole material becoming a wave...

Hi could someone please explain to me what is meant by the term wave speed because I am confused by the definition which states "how fast a point moves on the wave".

I would have a question to LIGO. How can LIGO detect the source of a gravity wave? It's a 2-dimensional detector, which has a certain length and a certain width, but no height. How does LIGO know the direction and distance of the source, and if this source is on the one side of LIGO or exactly...

Homework Statement I want to plot using Mathematica a wave packet entering a delta potential ##V(x) = s\delta(x) ## (s is the strength) but I need to get the physics right first and I'm having trouble with a a few parts. I need to compute the integral ## \int_{0}^{\infty} e^{-i\omega...

Homework Statement I am really confused with the equations. For traveling waves, in some places they write y = A cos (kx - wt) for waves traveling in the positive x-direction. Then some write y = A sin (wt - kx) for waves traveling in the positive x-direction while others write y = - A sin (wt...

Homework Statement Twelve identical mass-spring combos are lined up and set to oscillation. Two pictures of the same system taken at different times are shown. The crest-to-crest distance is 8.0 cm, and the maximum displacement of all the masses is 1.5 cm. 1) Explain how you can tell that a...

http://science.sciencemag.org/content/355/6326/673?utm_campaign=toc_sci-mag_2017-02-16&et_rid=34818699&et_cid=1169695 Bummer :frown:

Homework Statement Solve 2D wave eq. ##u_tt=c^2 \nabla^2u## in a circle of radius ##r=a## subject to $$u(t=0)=0\\ u_t(t=0)=\beta(r,\theta)\\u_r(r=a)=0\\$$and then symmetry for ##u_\theta(\theta=\pi)=u_\theta(\theta=-\pi)## and ##u(\theta=\pi)u(\theta=-\pi)##. Homework Equations Lot's I'm sure...

Homework Statement Two trains approach the train station from opposite sides each moving at an initialvelocity of 120 km/h with respect to the station and slowing down to a halt in 20seconds. If both trains are whistling at 5000 Hz, find the distance between the zeroand first order maxima as a...

Hi I am currently looking for a topic to write my essay on. My first idea was to talk about how waves altered in different beaches. (With this I mean the shape of the waves) I don't know much about waves and I can't seem to find good info on the internet. If you think there isn't much to write...

I'm studying for my electrodynamics exam and one of the past exam questions is: From the scalar and vector potentials, derive the homogenous wave equations for E and B fields in vacuum. I did derive the wave equation for the B field by simply taking the curl of the homogenous wave equation for...

Homework Statement A violin string is plucked to the shape of a triangle with initial displacement: y(x,0) = { 0.04x if 0 < x < L/4 (0.04/3)(L-x) if L/4 < x < L Find the displacement of the string at later times. Plot your result up to the n = 10...

can somebody explain to me how kelvin waves are working ? I just found, that the waves move along the coast due to the coriolis force, but I have no clue why this is happening.

What composes the E Field of the Electromagnetic Wave where "disturbances" for propagation occurs? If electromagnetic waves cause disturbances in the Electric Field… what “is” in this E Field which photons Interact with? I ask because in Vacuum, there are no electrons to excite. So what is...

Homework Statement Prove that ##\psi_n## in Eq. 2.85 is properly normalized by substituting generating functions in place of the Hermite polynomials that appear in the normalization integral, then equating the resulting Taylor series that you obtain on the two sides of your equation. As a...

The electromagnetic wave derivation uses the fact that charge enclosed is zero and it goes to obey plane wave equations. Lets say we were deriving a wave equation from maxwell's equations for electron wave motion, but we assume that charge enclosed is not zero, and come up with some...

Is "a light, particle or wave" an absolute question or a relative question? Should a light be considered as a particle or as a wave depends upon the relative size of the system? When considering a visible light relative to a basket ball should it be considered as particle, while a visible light...

Homework Statement Imagine a interference pattern like the common water-wave interference pattern. What effect would decreasing the distance between the 2 wave sources have on the interference pattern? Homework EquationsThe Attempt at a Solution A change in the distance between the two...

I would like to ask this question. In the double slit experiment on wave particle duality of photon, we know that the wave function collapses and the photon behave like a particle whenever we peek. Has anyone ever placed a second double slit behind the detector to see whether a particle regain...

Hello! So I'm really stuck in a personal quest to derive Kitaev's 1D p wave superconductivity model, and I'm stuck on the seemingly simplest part. 1. Homework Statement In the Bogluibov transformation, we get two coefficients from the equations |v_{k}|^{2}+ |u_{k}|^{2}= 1...

Homework Statement .[/B] On the course, I was asked a question: What is less absorbing electromagnetic wave: metal or glass? Explain why. The Attempt at a Solution Now, I'm not sure if i did it correctly. I answered that glass is less absorbing electromagnetic wave due to it's structure and...

Yaahh...After deploying all my grey matters on interference I just came to a conclusion that "What is wave?" Do we have the right pictorial diagram of a wave? But please don't through the the 'ficticious' thought I like too much, just answer "Why we get a dark 'fringe'? 'Fringe'?" Shouldn't we...

Homework Statement The extension in a string, obeying hooke’s law is Y when wave velocity in it is V. if extension is increased to 1.5Y, then wave velocity V’ becomes? 1) V' =V. 2)V'= 1.22V . 3)V'=1.5V. 4) V'=0.75V. Homework Equations wave velocity= frequency*wave length. The Attempt at a...

Homework Statement Hello- I'm having trouble understanding a problem: Consider a sealed 1D pipe of length L. At t=0, v=0 everywhere and the pressure is given by: P=P_0 +δP and δP = (p-bar)x/L P_0 and (p-bar) are both constants. and I'm supposed to find density (ϱ) as a function of x and t...

It is mentioned that subsystems don't have a wave function, in general. If two subsystems are entangled, there can be a wave function for the composite system, but not for each subsystem. Let's say you have two entangled photon pair.. it has a wave function but not for each separate photon...

So we know for a fact that an electron is a particle. The "wave" like properties are not waves at all, its just the wavefunction that is a mathematical wave which is used for getting probabilities for where the electron will end up. But what about a photon? When a charge oscillates, its gives...

Homework Statement In a large water tank experiment, water waves are generated with straight, parallel wave fronts, 3.00 m apart. The wave fronts pass through two openings 5.00 m apart in a long board. The end of the tank is 3.00 m beyond the board. Where would you stand, relative to the...

What has confused me for a long time is the interaction between superposition and entanglement. That is, what happens when one member of a pair of entangled particles passes through a filter that selects for an observable that is incompatible to the observable in which the pair is entangled...

1 - Huygens-Fresnel principle states that every point in a light wave is itself a wave source, 2 - light is made of photons, 3 - photons have a wavelength, they are QM objects. Hence my question : are photons the actual wave sources in Huygens-Fresnel principle ? Or are those two...

I have a concern about having some wave function psi, that is originally a superposition of many eigenstates (energies). Traditionally, it is said that the square of the coefficient of each of the component eigenfunctions represents the probability of measuring this particular energy eigenstate...

This article is about using P wave symmetry for super conductors, can you explain what a P wave is and why it is needed for super conduction please https://www.sciencedaily.com/releases/2017/01/170119084619.htm

Hi everyone, I'm having some difficulty comprehending "normal" transmission of stress/strain through a solid body and "shock" transmission of stress/strain. Imagine I have two bodies, one rigid - the other elastic. If the rigid body is fixed in space, and the elastic body is flying at the...

For the wave traveling towards left, the equations is Asin(kx + ωt). How does the same mathematical equation explain the possibility of two initial conditions. In the case of the wave traveling towards right, Asin(kx - ωt) and Asin(ωt - kx) gives two initial conditions Asin(kx) and - Asin(kx) on...

Homework Statement "assume that the three real functions ψ1,ψ2, and ψ3 are normalized and orthogonal. Normalize the following function" ψ1 - ψ21/(sqrt2) + ψ3sqrt(3)/sqrt(6)Homework Equations This is for a physical chemistry class. I haven't seen an example like this. All that is in our...

I would really like some confirmation / clarification on the following points that I am trying to understand in terms of modern physics. I would really appreciate if anyone might correct and complete my misunderstandings: 1 One can consider light as a wave. 2 As a particle, a photon may be...

Homework Statement The time for which the diode conducts is Homework Equations Using integration and differentiation Vc = 1 / C integral (current)(dt) The Attempt at a Solution Vs = -Vc Vm sin(wt) = -Vc = - (1/C) integral (Idt) now differentiate both sides to get expression for I that is...