Wave Definition and 999 Threads

Speed of a wave in a string is given by √(τ/μ) . But this speed is with respect to which reference frame? Since, the speed depends on τ and μ( which are independent of reference frame ), I can consider speed of wave independent of reference frame. But this is not so. From experiment, we know...

Sinusoidal wave form ? I am asking: We know that if a coil rotates in a transverse magnetic field a sinusoidal voltage is induced between its terminals. . My question now is: Why it is exactly sinusoidal in the shape and not any other wave shape?? .

The equation below (2.9) is also a linear differential equation. This equation also describes the wave phenomena. So, why is this equation not considered as wave equation? I have taken it from the optics book by Chapter two Eugene Hecht,5th edition ,Pearson.

Hello! (Wave) Let $$u_{tt}-c^2 u_{xx}=0, x \in \mathbb{R}, t>0 \\ u(x,0)=0, u_t(x,0)=g(x)$$ where $g \in C^1(\mathbb{R})$ with $g(x)>0$ for $x \in (0,1)$, $g(x)=0$ for $x \geq 1$ and $g(x)=-g(-x)$ for $x \leq 0$. I want to find the sets of $\{ (x,t): x \in \mathbb{R}, t \geq 0 \}$ where $u=0...

I've been following the derivations in the following video up until that point. I don't quite understand why does it imply that μ*ε=1/c^2. Thanks.

How can I calculate the capacitor needed for my wave energy collector? I have have build a wave energy collector. It consists of multiple coils in series with magnets moving up and down, following the waves underneath the unit. My multi-meter measures anywhere between 60 and 250 milli volts...

Hi, My teacher tasked me with a complex waveform question, i have looked for some time to find out how to tackle these, but i still do not know where to begin. Any help would be greatly appreciated, not look for an answer just a method. i=12sin(40*\pi t) + 4sin(120* \pi t - /3\pi) + 2sin(200...

In the wave equation## \frac {\partial^2 \psi} {\partial x^2}=\frac{1}{v^2}\frac{\partial^2 \psi}{\partial t^2}\tag{1}##, v is the speed of the wave propagation. With respect to which reference frame is this speed measured( in general)?

A clever new paper explores the notion that the reduced Planck's constant in the quantum analogy to Newton's constant for macroscopic quantities though a hybrid quantity that generalized the Compton wavelength and the Schwarzschild radius. This allows for a linkage between the Einstein equations...

How come a+a- ψn = nψn ? This is eq. 2.65 of Griffith, Introduction to Quantum Mechanics, 2e. I followed the previous operation from the following analysis but I cannot get anywhere with this statement. Kindly help me with it. Thank you for your time.

In a recent article by BBM in Physical Review Letters highlights another approach to link QM to Zeta to Prove R.H. There approach proved unsuccessful. I want to ask professional Physicists if the following new approach have merit in connecting the Zeta function to QM? This new line of attack...

Homework Statement A flute player hears four beats per second when she compares her note to a 587 Hz tuning fork (the note D). She can match the frequency of the tuning fork by pulling out the "tuning joint" to lengthen her flute slightly. What was her initial frequency? Homework Equations Not...

I have the following program that moves a wave on a string with fixed ends. The program solves the wave equation given a initial condition wave. The initial condition is a triangle wave splitting into two pulses. Here is the code written in Python: from numpy import * from matplotlib.pyplot...

Homework Statement The wave function of a particle is known to have the form $$u(r,\theta,\phi)=AR(r)f(\theta)\cos(2\phi)$$ where ##f## is an unknown function of ##\theta##. What can be predicted about the results of measuring (a) the z-component of angular momentum; (b) the square of the...

I am aware that in classical electrodynamics a metal exponentially attenuates TEM waves. I am wondering if this fact is sufficient to obtain estimates of the cross section of low energy gamma rays in metals. Obviously it would fail for higher energy gamma rays where Compton scattering and pair...

Is there a function that describes the collapsing of a wave function? Or does in happen instantaneously in theoretical terms. I do want to know what happens with the other possible states, whether they stay alive but in another form, or what's going on.

Hi, my answer is about the double slit experiment: the interference is observable with the water waves, them are particle in movment, but when we observe it with the electrons, what is the medium for those waves? Are the particles made of matter between the gun and the slits? Or is it something...

The wave function for fermions has to be anti-symmetric with respect to exchange of positions of electrons, but what if it depends on wave vector as well. Does they have to be exchanged as well, in other words, for two-electron system what is correct Ψ(r1,k1,r2,k2) = - Ψ(r2,k1,r1,k2) or...

Homework Statement Given the Z component of E inside a rectangular wave guide, Find the ratio of the maximum charge density on the plane x = 0 to the maximum charge density on the plane y = 0. Additionally, Find the ratio of the maximum surface current on the x = 0 plane to the maximum surface...

Homework Statement The left-hand end of a long horizontal stretched cord oscillates transversely in SHM with frequency 270 Hz and amplitude 2.4 cm . The cord is under a tension of 90 N and has a linear density 0.08 kg/m . At t=0, the end of the cord has an upward displacement of 2.1 cm and is...

Homework Statement Consider a plane monochromatic wave incident on a flat conducting surface. The incidence angle is ##θ##. The wave is polarized perpendicular to the plane of incidence. Find the radiation pressure (time-averaged force per unit area) exerted on the surface. Homework Equations...

Homework Statement An AC current is given by I= 475 sin( 9.43 t), with I in milliamperes and t in milliseconds. Find the frequency. Homework Equations w = 2pi*f The Attempt at a Solution I got 9.43/2pi which is 1.5 Hz, but that is wrong. I honestly have no idea what to do to find the Hz.

Maxwell equation in absence of charges and currents are $$\nabla \cdot \bf{E} = 0 \\ \nabla\cdot B=0 \\ \nabla \times E=-\frac{\partial B}{\partial t} \\\nabla \times B=\mu \epsilon \frac{\partial E}{\partial t}$$ Wave equation is $$\nabla ^2 \bf{E}=\mu \epsilon \frac{\partial^2...

Given a source of electrons, like from an electron gun. Physicists call these freely traveling particles and often use a Gaussian wave packet to represent them with the group velocity being precisely defined as the velocity of the center of the packets. But if we do not measure the position of...

A professor from a UK university who is a member of LIGO kindly video called me the other day regarding potential PhD projects and said that a lot of gravitational research isn't about the dynamics and source-model nor application of general relativity but high performance computation and big...

Within the context of the de Broglie-Bohm pilot-wave theory, can anyone explain what the pilot wave is in physical terms? I’m having a hard time understanding how, for example, the pilot wave influences the trajectory of a photon in the double-slit experiment. Are we dealing with...

According to the old thery of light the energy carried by by a wave is proportional to the amplitude of the electric field not to the frequency as Planck proposed, so an eletromagnetic radiation in the gamma spectrum carry the same energy as a radio one if their amplitude is the same? They only...

Lets assume there is an observable represented by the operator, ##\hat{A}##. It follow (I think) that the observed values and allowed states obeys an equation of the following form\begin{equation}\hat{A}|\psi^i\rangle=\lambda_f|\psi_f\rangle\end{equation} where $$|\psi^i\rangle = initial \ \...

In Shankars "Principle of Quantum Mechanics" in Chapter 4, page 122, he explains what the "Collapse of the State Vector" means. I get that upon measurement, the wave function can be written as a linear combination of the eigenvectors belonging to a operator which corresponds to the...

Homework Statement I want to find the Fourier series of the sawtooth function in terms of real sine and cosine functions by using the formula: $$f_p (t)=\sum^\infty_{k=-\infty} c_k \exp \left(j2\pi \frac{k}{T}t \right) \tag{1}$$ This gives the Fourier series of a periodic function, with the...

Would there be destructive interference if I had two waves that are superimposed and the peak of one wave met the trough of the other but they both have different amplitudes? If there isn't total destructive interference, then what does the final wave look like?

Let me start with a short disclaimer - I am not saying that QM is wrong or things like that. And I very well understand that my argument is not physical, more philosophical one, which may be considered as inappropriate here. Still, my intentions are good and I hope for some understanding. When...

I would like to approximate a plane electromagnetic wave with a very large sum of the following. Let an infinite line, say the z axis, have a electric polarization on that line and perpendicular to that line, say the x direction to be specific given by, P(z,t) = pcos(kz-ωt). The polarization...

Homework Statement Homework Equations x(t) = A cos (2pi * f * t) v (t) = - vmax sin (2pi * f * t) vmax = (sqrt of k/m) * A v = circumference/period The Attempt at a Solution I do not know how to find the velocity as question only provides amplitude and i don't know how to find period using...

Homework Statement Consider a glass plate of refraction index n and thickness ## \Delta x ## placed between a point monochromatic source S and an observer O, as in picture. (a) Prove that, if absorption from the plate is neglegible, then the effect on the wave received by O is the add of a...

Homework Statement A 300 MHz plane wave propagating through a non-conducting medium having relative permeability= 1, relative permittivity= 78.What is the velocity of light in this medium? Homework EquationsThe Attempt at a Solution n=√(78) v=c/n =3*108/√78[/B]

First time poster long time reader. If i have a half wave dipole antenna with a certain length and I am using a VCO to drive that antenna at lower driving frequency do i get EM at the length of twice the length of the antenna but just at a slower emission rate? example, if i have a half wave...

Homework Statement I am having trouble with part d, where they ask me to prove that the wave function is already normalized The Attempt at a Solution But that clearly doesn't give me 1. I tried to use spherical coordinates since it is in 3D? Not really sure how to proceed. EDIT: I realize...

Homework Statement Two plane gravitational waves with TT (transverse-traceless) amplitudes, ##A^{\mu\nu}## and ##B^{\mu\nu}##, are said to have orthogonal polarizations if ##(A^{\mu\nu})^*B_{\mu\nu}=0##, where ##(A^{\mu\nu})^*## is the complex conjugate of ##A^{\mu\nu}##. Show that a 45 degree...

Homework Statement Determine the wavelength of light being used to create the interference pattern in 3 different ways from the given data. -The angle to the 8th maximum is 1.12° -The distance from the slits to the screen is 302 cm -The distance from the first minimum to the fifth minimum is...

Homework Statement Show that the 3 wave functions are normalizedHomework Equations The Attempt at a Solution [/B] The above image is my initial attempt at the first equation. I was told the way to find out if its normalized is to use: ##\int^{+\infty}_{-\infty} \Psi^2 dx## = 1 but I...

Homework Statement There is a resonance box with one end cloesd and the other end open. The box reinforces the sound of the tuning fork. That sound has frequency of 440 Hz sound velocity is 340 m/s a.) What is the basis of the phenomenon in question? b.) define the shortest possible length of...

Homework Statement Two identical loudspeakers are driven in phase by a common oscillator at 800 Hz and face each other at a distance of 1.25 m. Locate the points along the line joining the two speakers where relative minima of sound pressure amplitude would be expected. Homework Equations v...

Homework Statement A longitudinal wave is propagated through a medium. The distance from one max compression to the next is X meters, and its speed is Y m/s. Express the frequency of the waves in terms of x and y. Homework Equations velocity of a wave= Wavelength x Frequency Velocity of a wave...

Hi, guys. I'm interrest in the question about how optical (laser) resonator can generates the standing wave? As i know, there is a condition that the resonator base (lenght between two mirrors) should be multiple to the length of the wave. (L=k*(lamda/2)). But in practice no one never measures...

Hi there, I was wondering what the relationship between the photon and the electromagnetic wave is? Is the photon traveling on that wave like a surfer is riding a wave? :-) Thanks in advance!

Homework Statement A metal bar is attached into a vice in the middle. Bar is hit with a hammer creating a longitudinal standing wave find the two lowest frequencies. Bar's length l= 3m wave velocity = 5100m/s Homework Equations wave equation ## v = \lambda * f ## The Attempt at a Solution...

Homework Statement I'm a pharmacologist and I have a modern physics course to do. This is not my field and I'm completely lost... We were given this problem to do. Thanks a lot in advance. Consider a potential where U(x) = 0 for x ≤ 0 U(x) = -3E for x > 0 Consider a particle of energy E...

Heads up, I only recently got into quantum mechanics and don't feel like I got a solid grasp on the material yet. 1. Homework Statement Given is the wave function of a free particle in one dimension: \begin{equation} \psi(x,0) = \left( \frac{2}{\pi a^2} \right)^{1/4} e^{i k_0 x} e^{-x^2/a^2}...

Hi, I'm a second year undergrad and we've covered the heat equation, \begin{equation} ∇^{2}\Psi = \frac{1}{c^{2}}\frac{\partial^2 \Psi}{\partial t^2} \end{equation} and the wave equation, \begin{equation} D∇^{2}u= \frac{\partial u}{\partial t} \end{equation} in our differential equations...