Wave Definition and 999 Threads

I understand how waves undergo superposition. However, for a standing wave, the reflected wave is a mirror opposite of the incoming wave. By the superposition principle, won’t the 2 waves add up to 0, at all points?

I am having problems writing the initials conditions.

qn iv. I understand that when 1.5 periods pass, every compression will become rarefaction, and every rarefaction will become compression(someone please correct if wrong) but the answer key shows something else. I'm interpreting the answer key drawing to be 1 compression and 4 rarefactions...

A massless scalar field in a curved spacetime propagates as $$(-g)^{-1/2}\partial_\mu(-g)^{1/2}g^{\mu\nu}\partial_\nu \psi=0 .$$ Suppose the gravitational field is weak, and ##g_{\mu\nu}=\eta_{\mu\nu}+\epsilon \gamma_{\mu\nu}## where ##\epsilon## is the perturbation parameter. And let the field...

Hi, I am looking for a short document discussing the usage of the wave vector. Any recommendations? Thank you!

## \frac {\partial^2 \psi} {\partial t^2} = v^2 \frac {\partial^2 \psi} {\partial x^2} ## has solution ## \psi (x, t) = \sum_{m=0}^\infty A_m \sin(k_mx + \alpha_m)sin(\omegat + \beta_m) ## The boundary conditions I can discern $$ \psi (0, t) = 0 $$ $$ \frac {\partial \psi} {\partial x} (L, t)...

hello matrix and wave formulation of QM are equivalent theories i.e they yield the same results Which one is most frequentely used by professional scientists in solving real problems and why ?

I think increasing the damping would decrease the amplitude and increase the Period (T). But, what I'm really unsure about is the frequency, wavelength and wave speed. Would it be no effect on those three? Because if dampening acts like friction, wouldn't it slow down the wave/ increase speed?

how we get "e^(ikr)"...? Plz ans me... Thanks

Hey there! I have two questions regarding the Double Slit Experiment and the Wave Function Collapse. How effective does a measuring device have to be to cause a collapse? As in, say that every second the device has a 50% chance to turn off or on for one second, does the collapse still occur...

How can we find a equation of a 1D sound wave in a non-differential form in an ideal gas with viscosity? How does the damping work? How does the wave lose energy at each layer as it propagates? To be clear I am looking for a simple exponential-sinusoidal function for it just in the case of...

This is probably kind of dumb, but it's really bothering me for some reason. I originally saw traveling wave solutions to the wave equation as ##f(kx−\omega t)## for right traveling (as t gets bigger, x needs to be bigger to "match" it's previous value) and ##f(kx+\omega t)## for left-traveling...

I know the answer would be yes, but why? In class, I learned that energy is scalar and cannot be negative (at least in undergraduate class). Thus adding two sources of energy should result in a higher level of energy in general. But here for wave, if we have 2 waves that do destructive...

As I learn in class, when EM wave goes from medium 1 to medium 2, there are 3 possibilities that can happen Totally transmitted (i.e when the angle of incident is 0 degree) Partially transmitted and reflected (i.e when the angle of incident is between 0 and critical angle) Total internal...

I don't know if this is the ideal sub-forum for this but I'd like to know more about this very recent activity I first saw here >>>>>' It looks like this could be some actually testable, actual breakthrough advances in Physics and the evolution of our Universe. Any comments appreciated.

Very early in the development of thermodynamics, it was realized that the 2nd Law of Thermodynamics is not a law fundamental to the fabric of our cosmos, but only becomes true in the limit of the number of particles. It was none other than Boltzmann himself who realized and articulated this...

[New poster has been reminded by the Mentors to show their work on schoolwork problems] I have tried many times to solve this problem, but can't understand how to get the value of Im and hence cannot find the Peak & other values of the load current. Please help me to solve...

(a) Let the center of the concentric spheres be the origin at ##r=0##, where r is the radius defined in spherical coordinates. The potential is given by the piece-wise function $$V(r)=\infty, r<a$$ $$V(r)=0, a<r<R$$ $$V(r)=\infty, r<a$$ (b) we solve the Schrodinger equation and obtain...

The equation of incoming wave is ##y_1=A \sin(\omega t - kx)## and the equation of the reflected wave will be ##y_2=-A \sin (\omega t+kx)## since the wave travels in opposite direction and undergoes phase change of ##\pi## The equation of stationary wave will be: $$y_s=y_1+y_2$$ $$=A...

This is the set up to produce stationary wave. The oscillator on the left will produce wave on water surface then this wave will travel to right, reflected at the tank and the incoming and reflected wave will superpose to form stationary wave. My teacher said when the water wave hits the tank...

Hi hi, I'm looking into how temperature affects waves, but I don't know too much about this, in how temperature mixes with all of this, I have this questions: We have a particle vibrating at frequency ##f## at a certain temperature ##t_p##, and a medium with other temperature ##t_m1##. If the...

Hi hi, I'm confused about how to mix this two concepts, actually the wave equation: ##\frac {\partial^2 u} {\partial t^2} = v_x^2 \frac {\partial^2 u} {\partial x^2} + v_y^2\frac {\partial^2 u} {\partial y^2} + force## The equation will apply the rule all over the space, but I have the next...

For normalizing this wave function, I began by finding the complex conjugate of psi and then multiplied it with the original psi. Now what I am getting is A^2 integral exp(2cx^2-4ax) dx = 1 Now I am not getting how to solve this exponential term. I tried by completing the square method but it is...

Hi, In Problem 9.12 of Griffiths Introduction to Electrodynamics, 4th edition (Problem 9.11 3rd edition), in the problem, he says that one can calculate the average energy density and Poynting vector as using the formula I don't really understand how to do...

Calculate the wavelength for an ##E_x## polarized wave traveling through an anisotropic material with ##\overline{\overline{\epsilon}}=\epsilon_0diag({0.5, 2, 1})\text{ and }\overline{\overline{\mu}}=2\mu_0## in: a. the y direction b. the z direction Leave answers in terms of the free space...

I'm not sure where this belongs, I'm guessing biomedical, but I'm interested from a physics perspective. Do neurons generate an electromagnetic field? In other words, all the neural activity in the brain, does it generate electromagnetic fields? If so, what are the details of these fields? I...

ψ(y,t)= -2A sinky sin wt Why is this called a standing wave?

For the sake of this question, I am primarily concerned with the position wave function. So, from my understanding, the wave function seems to 'collapse' to a few states apon measurement. We know this because, if the same particle is measured again shortly after this, it will generally remain in...

I = 1/2 ρvR²w² I = 1/2 *1.2kg/m³*340m/s*(10 x 10^-6m)²*(2π*440/s)² I = 0.16 W/m² This is my answer which does not match the given answer. Am I doing wrong?

why was the schrodinger equation for the relativistic wave unsuccessful?

I am studying Quantum physics and I'm having some problems to understand what is the Wave Amplitude since I can't find a physical significance to it. Does anyone ever heard something that come close to a physical significance?

Velocity of photon allways is c(photon is massless particle).While velocity of EM wave in medium < c.So does velocity of photon need not allways equal velocity of EM wave?

What I chose to do was analyze what happened at x=0. At x=0 I know sin of whatever will be 0. So 0=sin(kx-wt) and since x=0, w=Arcsin(0)/t. But this doesn't make sense because the answer isn't 0, its 0.695.

The wave function ψ(x) of a particle confined to 0 ≤ x ≤ L is given by ψ(x) = Ax, ψ(x) = 0 for x < 0 and x > L. When the wave function is normalized, the probability density at coordinate x has the value? (A) 2x/L^2. (B) 2x^2 / L^2. (C) 2x^2 /L^3. (D) 3x^2 / L^3. (E) 3x^3 / L^3 Ans : D

This is more of a conceptual question. To find the horizontal velocity as a function of time for the above wave function, you take its partial t derivative and insert x=4. In other words the function would be -2.4sin(1-12t). Im wondering why you take the partial t derivative and not to partial...

Hi, I have this question about the variation of wavelength and frequency as light travels to an environment with a different index. As we have learned in class, celerity can change as light enters a different environment, however frequency and wavelenght are independent and remain constant...

I am having a trouble to understand why the helium's wave function (in which we are ignoring the electric interaction between the electrons, as well the motion and problems that arise in considering the nucleus in the wave function) can be written as the product of the wave function of both...

So what I did was made the two equations equal each other. A lot of stuff cancels out and I end up with x=-vt. My issue is that t isn't given and I am not entirely sure how to get it. I don't think taking the partitial derivative of time will be any help nor the partial derivative of...

Is there an uncertainty between amplitude and phase in classical quasi-monochromatic light?(E(t)=a(t)cos(phi(t)-omega_0*t))If it exist, what is the relation between classical and quantum uncertainty(delta I* delta phi>=1/2)?

$$Δφ = 2π \frac{L_2 - L_1}{λ}$$ $$Δφ = 2π \frac{\sqrt{0.016^2+10^2}-\sqrt{0.014^2+10^2}}{560*10^{-9}}$$ $$Δφ = 33.659 rad$$Answer = 2.24 rad (unsure if the answer provided is correct/wrong)

I know how to work through this problem but I have a question on the initial separation of the wave function. Assuming ##\psi(\rho, \phi) = R(\rho)\Phi(\phi)## then for the azimuthal part of the wavefunction we have ##\Phi(\phi)=B\left(\frac \rho\Delta cos\phi+sin\phi\right)##, but this function...

Does mean velocity of particle equal group velocity of wave packet in QM?If they do not equal which of them is classical velocity?

It is a rather simple question: In my textbook it writes something like: $$\frac {\partial \Psi} {\partial t}= \frac{i\hbar}{2m}\frac {\partial^2 \Psi} {\partial x^2}- \frac{i}{\hbar}V\Psi$$ $$\frac {\partial \Psi^*} {\partial t}= -\frac{i\hbar}{2m}\frac {\partial^2 \Psi^*} {\partial...

since, in order to view the shape changes in our wave packet we are presented with the taylor expansion of the frequency ω(k) = ω(k0) + (k − k0)dω/dk + 1/2*(k − k0)^2 (d^2ω/dk^2) we are told that only the third term that is the 1/2*(k − k0)^2 (d^2ω/dk^2) contributes to change in shape of the...

They say wave function is different to quantum field. Then what is the difference between EM wave and EM field?(By the way :Is that EM wave the wave function of photons?).It seem to me EM wave is the wave of EM field?

why the general wave vector q (in the proof of Bloch theorem in Ashcroft Mermin) is represented by k-K, where k is in the 1st BZ ? why not q=k+K ( usual vector form) what is special about k-K?

I´´m confused. How can a single photon in the lightspectrum with wavelength of a few hundert nanometers go through both slits in the double slit experiment at the same time. I understand the wave- particle duality and the concepts in principle. My confusion is in the context of little wavelength...

We know that the non-relativistic propagator describes the probability for a particle to go from one spatial point at certain time to a different one at a later time. I came across an expression (lecture notes) relating ##\Psi(x,t)##, an initial wave function and the propagator. Applying the...

Reading the classical Feynman lectures, I encounter the formula(19.53) that gives the radial component of the wave function: $$ F_{n,l}(\rho)=\frac{e^{-\alpha\rho}}{\rho}\sum_{k=l+1}^n a_k \rho^k $$ that, for ##n=l+1## becomes $$ F_{n,l}=\frac{e^{-\rho/n}}{\rho}a_n\rho^n $$ To find ##a_n## I...