Wave Definition and 999 Threads

I just started learning about waves from an introductory calculus-based textbook (HRK) and there was a part describing what happens when a wave on a string transmits into another string (with different mass density). It said that if the wave is going into a string with a larger mass density, the...

A superconductor has the shape of a uniform plane wave. If it is flowed by a direct current, is it emitting electromagnetic radiation or not?

P.S. I tried to clean up this post, but the program does not seem to be working correctly. When I click on "preview" I get one thing, but when I go back to my original text, it does not match the preview. I plugged the expressions for mu and omega into the equation for total energy and...

A plane wave (which can be a scalar function like air pressure, a vector function like the electric field ##\bf{E}## or a tensor field like the spacetime metric ##g_{\mu\nu}##) is a function of $$\xi = \omega t - {\bf{k} \cdot \bf{x}} = k_\sigma x^\sigma.$$ We call ##k_0## the wave vector. The...

If wave function requires observation to collapse, who or what may have been the observer during the billions of years before the emergence of life?

Hi, would gravitons theoretically act like photons? They're both particles and waves at the same time. Is there anything we can use from what we know about photons and use them to understand gravitons? Thanks Josiah

What will happen with the electromagnetic wave reaching an antenna when this antenna is not resonant on the frequency of the wave: will it reflect from antenna or pass through it? Thank you

Hi. To my understanding, the mathematical justification of various superposition principles in physics is that the sum of solutions to a linear differential equations is again a solution to the same equation. This justification works for solutions of the wave equation...

I believe I have solved parts (a) and (b) correctly. I'll first normalise ##\tilde{\phi}\left(p\right)## since I have found that doing so and then Fourier-transforming it to return ##\psi\left(x\right)## keeps the resultant (position) wave packet normalised...

I am trying to follow through a derivation of the solution to the wave equation governing a string with fixed ends via separation of variables but I am stuck at the step which concludes ‘m’ must be a natural number 1,2,3,… etc. as opposed to an integer. After analysing each case: m > 0, m = 0...

Hello,There is a model which tunes a plane wave using certain expressions which resembles the spherical to cartesian coordinates. There are two types of definitions: propogation normal and electric field vector. Why they put in propogation normal exactly the spherical to cartesian to represent...

If I have a system of bosons described by a wave function that can be separated into a spatial function and a spin function, do the spatial and spin functions have to be both symetric? Or can they be anti-symetric and symetry be attained only when we consider the whole wave function?

Will the probability density of a wave function be affected by length contraction due to special relativity?

Im utterly confused about this video and I would like some opinions about it: "How Superposition Causes Length Contraction -- And Explains the Principle of Relativity" Approximately content: 1) Length contraction is entirely physical (shorter molecular bonds??). 2) Oliver Heaviside's retarded...

the solution for the infinite num case the problem is that i only could reach the condition that the coefficients are zero when i substituted n=0 , i am reaching two independent variables i am not sure what am i doing wrong that's preventing me from getting a similar result to them "that...

I continue my reading of Griffiths electrodynamics (chapter 9, electromagnetic waves) and I got stuck on this: Author tries to prove a stretched string supports wave motion and I found it very difficult to grasp. In the second equation, why can we replace sin function with a tangents really...

My idea is as follows. Each mode of the quark field is characterized by a wave vector k. Each wave vector corresponds to a point in k-space. This set of points representing different modes forms a manifold. Each point in k-space can be assigned a three-dimensional vector space that represents...

Suppose a particle in a medium is displaced from its mean position by giving some energy and it is released. Due to property of elasticity and inertia it starts to vibrate about its mean position and due to interactions with other particles of medium they also vibrate in some later time. The...

Why does the phase of the reflected wave from a denser medium change?

How does QFT treat the Young’s DSE? Is there a wave function (wave packet) attached (and created at the moment of launching of the photon) or the modes of the EM quantum field are pre-existing due to experimental configuration (including the screen) and do they play the role the wave function is...

I want to know that when a charged particle accelerates then the electromagnetic wave so produced will loose it's strength or can say fades with distance or not ? If yes then what happens to its frequency and also tell me if electromagnetic waves fades away with increasing distance from the...

hi, I'm solving this statement, We split into parts Can some expert in Quantum say that my working is professional? Kind wishes to you

Hi, I try and solve this problem I have solved the problem in different parts But me not sure how to plot the graph. Maybe someone knows? Merci

TL;DR Summary: Question on deriving the complex irreducible solution form for simple harmonic motions based on time translation invariant. Reference textbook “The Physics of Waves” in MIT website: https://ocw.mit.edu/courses/8-03sc-...es-fall-2016/resources/mit8_03scf16_textbook/ Chapter 1 -...

Many more questions....please enlighten me on this topic. thank you!

Question from someone scarcely more knowledgeable on QM than a layperson. To my understanding, early in QM's study, some thought observation by a conscious being was required to collapse a wave function. I was told here that said Copenhagen interpretation(?) is only considered by people like...

There is a gravitational wave spacetime described by$$g = a(u) (x^2-y^2)du^2 + 2du dw + dx^2 + dy^2$$There is one obvious Killing vector field, ##\partial/\partial w \equiv \partial_w##. To find some more, it's suggested to try:$$X = xf(u) \frac{\partial}{\partial w} + p(u)...

I have tried to draw the diagram and would just like feedback on it to know whether it is correct or not. Please keep in mind this was done roughly. Thanks

I have heard that the phase velocity of matter waves can be represented as c^2/v. But if the wavelength of these matter waves goes to zero as momentum approaches infinity and v approaches c, then does this mean that the frequency of the matter waves approaches infinity, to give the matter wave a...

From my understanding, you can equate ψ1(x) and ψ2(x) at the boundary of x = a, so I plugged in the values of a into x for both equations and I got ψ1(x) = 0 and ψ2(x) = ## (a-d)^2-c ##. I am a bit stuck on where to go from here.

In part (c), I have no problem if the string could stretch, but consider an inextensible string. This could still form a standing wave, according to google. But then how is the string (the wave) equal to L? So can we actually equate lambda/4 with L? i.e. it is curved and varies with amplitude...

Hi, I am doing my thesis on quantum entanglement and I don't seem to wrap my head around what really happens to an entangled system during a local measurement. I happen to know that information can't travel faster than light I could believe that the collapse of the wave function wouldn't allow...

I have been taught that speed of pulse is v = √(T/μ), but here tension varies at each point therefore I cannot just simply apply the formula. I think integration would be needed, I tried but ended up nowhere. Can someone help me find the time?

I know the way to solve the first part is to find <ψ|Αψ> and compare it with <ψΑ|ψ>. This comparison can be done through an integral representation where we take ψ* and act A on ψ to be the integrand, or act A on ψ* and multiply by ψ for the integrand. If the integrals are the same, then the...

Since I know from the equation the type of particle and the distance L, I thought of equating the first relevant equation to the second equation. Since n = 1, 2, 3 ..., I thought by equating the two equations I could get k = 1, 4, 9... and have the two constants equal each other. The two...

A wave pulse moves along a stretched rope in the direction shown. Which diagram shows the variation with time t of the displacement s of the particle P in the rope? A B C D my answer was c because i thought that the particle would move in the same way the wave was coming...

the diagram. i found that the phase difference between them is 100º but how is the answer 260 can someone please explain?

Hello, It has been difficult to find a clear answer to this question. I've found some sources stating that the power of a sound wave depends upon both amplitude and frequency. I've found other sources stating that the power of a sound only depends on amplitude. I've found sources stating...

Why do we say that wave amplitude tells us where we are likely to find the particle versus where we are likely to find the wave from the particle? Isn't the later a more accurate description of the QM math?

Hi, I am confused by the two concepts. How are they related? So, my interpretation is that a standing wave can happen without resonance. Resonance happens when a standing wave passes energy to another object, making it vibrate. Is that right? But some say a standing wave is an example of resonance?

According to Einstein light would be a particle and a wave. So I infer that it propagates in vacuum in form of waves of little bullets (particles). This explanation is very insuficient. So tell me how do waves increase in size since it's made of little bullets (particles)... a wave gets...

Zero does not have an inverse. And y=0 does not have an inverse. Does the wave form y=0 for all x have an inverse?

For this, The two statements highlighted do not seem to agree. I think the first statement highlighted is referring to A as initial amplitude (which we can denote ##A_i##) of the traveling waves before there constructive interference to form antinodes with an amplitude 2A and nodes of an...

I’ve read that the Ca2+ channels in neurons can be manipulated through the use of certain radio wave frequencies. And the resulting internal/external charge differential will cause the neurons to fire. Does anyone have any more insight into that?

According to Maxwell’s Equations, the speed an EM plane wave in free space, far from its source, is determined by the electric constant, ε0, and the magnetic constant, μ0, such that c = 1/√( ε0 μ0). The units of ε0 are capacitance per unit length and the units of μ0 are inductance per unit...

Sometimes I cannot imagine light as the popular Maxwell's blue and red electric and magnetic wave https://simply.science/images/content/physics/Electromagnetism/em_waves/emv.jpg but I found the image below to be the more accurate representation of how light actually looks like as waves...

Hello, My name is Josip Jakovac, i am a student of the theoretical solid state physics phd studies. First I want to apologize if my question has already been answered somewhere here, I googled around a lot, and found nothing similar. My problem is that I need to apply TBA to Graphene. I went...

In the picture below we have two identical orbitals A and B and the system has left-right symmetry. I use the notation ##|n_{A \uparrow}, n_{A \downarrow},n_{B \uparrow},n_{B \downarrow}>## which for example ##n_{A \uparrow}## indicates the number of spin-up electrons in the orbital A. I would...

https://www.sciencealert.com/uncanny-coincidence-fast-radio-burst-detected-after-gravitational-wave-event