Wave Definition and 999 Threads

As you can see from figure 4.4 from Griffiths book on QM, the radial wave function of the hydrogen atom has clear points where ## |R_{nl} (r)|^2 = 0 ##. My question is three fold: First, how is the electron able to traverse this region? My intuition is that with the uncertainty principle, the...

Hello all, First of all, I am aware that dissonance and consonance between pitches also depend to an extent by culture and musical origin but there also seems to be some degree of objective perception among people that can be explained scientifically. Also, I'm very new to this so I could be...

Hello all, I would like to know why an electron is accelerated in a linear accelerator because of the microwaves emitted by a magnetron?. Can someone tell me what are the relevant physics equations and what is the role of skin-effect here? Thanks a lot.

In the (b),I have some questions: (1) Does it mean ψ can be real or not real? (2) Why do the solutions of linear combination must have the same energy? As I know, these solutions are often different, as long as they are eigenvalues of time-independent Schrodinger equation. (3) In the sentence...

I was wondering how the energy and amplitude change over a distance

This question concerns a section from the book Modern Physics by James Rohlf. http://srv3.imgonline.com.ua/result_img/imgonline-com-ua-twotoone-Bs4zgy7pruqG.png He shows that the form of the Wave equation for light remains invariant under a Lorentz boost (4.42)...

Hi, i am doing an introductory course in quantum mechanics (that would be equal to first two chapters in griffith's quantum mechanics). I have the doubt that what exactly do we consider in quantum mechanics. Let me say like the electron is a particle and when we will observe it will have a...

I will be very grateful if someone could explain to me the following, in the most simple terms, f being a wave function : " ...f = f(x–ct). Let me explain the minus sign and the c in the argument. Time and space are interchangeable in the argument, provided we measure time in the ‘right’ units...

By addition of transverse wave, I can get a beat. ## y_1 = A\ \sin (\omega_1 t + kx)\\ y_2 = A\ \sin(\omega_2 t + kx)\\ --------------------------------- + \\ y_1 + y_2 = 2A\ \cos(\frac{\omega_1-\omega_2}{2} \ t) \sin(\frac{\omega_1+\omega_2}{2} \ t + kx)## So, I get new amplitude as a function...

Two identical tuning forks vibrate at 256 Hz. One of them is then loaded with a drop of wax, after which 6 beats/s are heard. The period of the loaded tuning fork is? So, as the uploaded pictures shows, I did solve the problem, but I'm not sure why the f1 frequency is bigger than f2. I mean how...

Homework Statement If a wave y(x, t) = (6.0 mm) sin(kx + (600 rad/s)t + θ) travels along a string, how much time does any given point on the string take to move between displacements y=+2.0 mm and y=-2.0 mm? Homework Equations ω=2πf (but it's not necessary in this problem, this problem just...

Hey, guys. There is an interesting question about EM waves. I know electricity is transferred on transmission line as electromagnetic wave. But electromagnetic wave is one type of transverse wave, then how is AC electricity like? I feel it hard to imagine it. Besides, conductors could be used...

The wave function is an exponential function, if I plot the real part of it, I don't get a wave graph like sine or cosine function, Why the wave function is not represented by a trigonometric ratio instead. Also, the wave function cannot be plotted since it is imaginary, why is it imaginary? Thanks

In his seminal paper on Special Relativity: On the Electrodynamics of Moving Bodies, Einstein derives a formula for the Relativistic Doppler effect. See this section: § 7. Theory of Doppler's Principle and of AberrationThe formula is: In this Wiki article, the same formula is derived. The...

Homework Statement Homework Equations N/A The Attempt at a Solution I can't even understand the question and what is happening in the situation :(

Any function of the form f(x+ct) or f(x-ct) can be a solution to a wave equation - including the electromagnetic wave equation generated by combining maxwell's equations. Light is an electromagnetic wave which obeys maxwell's equations. If you were to meausure the electric field of light, is it...

Hello, A professor once told me that light can really do it. Is anyone knows about the phenomenon , and can explain me about it?

Homework Statement Link: http://i.imgur.com/klFmtTH.png Homework Equations a_0=\frac{1}{T_0}\int ^{T_0}_{0}x(t)dt a_n=\frac{2}{T_0}\int ^{\frac{T_0}{2}}_{\frac{-T_0}{2}}x(t)cos(n\omega t)dt \omega =2\pi f=\frac{2\pi}{T_0} The Attempt at a Solution Firstly, x(t) is an even function because...

The sound horizon is the distance that a wave of plasma can move from the end of Inflation to Recombination (roughly 300,000 years). In several papers and talks, this is described as a moving wave (see https://www.youtube.com/watch?v=JSqIBRbQmb0 at the 23 minute mark). The velocity of the wave...

I'm reading Gasiorowicz's Quantum Physics and at the beggining of chapter 2, SG introduces the concept of "wave packet" and gaussian functions associated to them. The first attached image is the 28th page of the book's 1st edition I suppose, and my question is about the paragraph inside the red...

Hi all, I remember the standing wave is introduced in a chapter of mechanical wave in my undergraduate physics times ago. It is said that two waves of the same frequency propagating the opposite directions will form a standing wave in space. I wonder if it is possible to produce the standing...

I tried to come up with a simple calculus-free explanation for why the energy in a sound wave is proportional to the square of the wave's amplitude for my musical acoustics class. I think this makes sense, and seems to just be an elaboration of what Donald Hall writes, but I haven't seen it...

Hi! For the probability interpretation of wave functions to work, the latter have to be square integrable and therefore, they vanish at infinity. I'm reading Gasiorowicz's Quantum Physics and, as you can see in the attached image of the page, he works his way to find the momentum operator. My...

Is wave a physical object or its just a model?

Hallow, if we say electron is a wave, do we mean it oscillates up and down as is moves through space? I am lost please.

Hi all, Whew, last question for a while: I think I already know the answer, but want to confirm (e..g, I think this thread basically answers the question, https://www.physicsforums.com/threads/propagation-of-wavefunction.152053/) As an example, let's say I have an electron (in free space or...

Given that we can satisfy the wave equation with a simple sine & cosine wave function (the real part of the complex wave function) in classical mechanics, why do we use the complex wave function in EM theories? In QM it is obvious that it gets more mathematically more consistent. Out of curiosity.

Homework Statement [/B]A traveling wave on a string is described by , 0.0050 sin[4.0 (rad/s) t + 0.50 (rad/m)x] . (a) Does this wave retain its shape as it travels? (b) In what direction does the wave travel? (c) What is the wave traveling speed? Homework Equations None. The Attempt at a...

I have a question about why the duration of the gravitational wave signal detected by LIGO was 0.25 seconds or so. I think I understand correctly that as the two binary black holes rotate around each other and move closer together there is a loss of angular momentum that is converted to...

As an exercise, I am trying to solve the 2nd-order wave equation: $$ \frac {\partial ^2 E}{\partial t^2} = c^2 \frac {\partial ^2 E}{\partial z^2} $$ Over a domain of (in SI units): ## z = [0,L=5]##m, ##t = [0,t_{max} = 5]##s, ##c = 1## m/s and boundary/initial conditions: ## E(z[0]=0,t) =...

Homework Statement Two strings are stretched tautly parallel to each other. The length of one is L1 and the length of the other is L2(>L1). When both are simultaneously made to undergo fundamental vibration, beats can be heard at a frequency n. The waves in both strings travel at the same...

Hello Guys, I'm building a vertical wave machine. I have a big bearing [2] (more like an eccentric) which is rotating by an electric motor with a constant speed of 0.359 rad/sec. When 3/4 of the bearing touches bearing [1] it supposed to rotate it a 1/4 turn, which as a result the ladder with...

I was reading the thread about wave particle duality linked from the newsletter, and I noticed it said (to use my own words) that the conflict between wave and particle dynamics can be avoided by using operator dynamics instead. Unfortunately, in the case of phonons, I've never seen a...

Can all seasoned physicists please confirm if it is true that wave particle duality is really wrong as when Bill stated in the decoherence branches thread "This is a little different than what you will find in a beginner text becauise it doesn't use the wave particle duality which is wrong - but...

why wave with lower frequency produce heat? please explain to me

Fermat’s principle states that light follows the path of least time. In textbooks, a specific formulation of Fermat’s principle is about the optical path between two points, A and B: How can a ray of light, emitted from point A, reach point B? Suppose that there is a plane wave in free space...

Hi all, I am reading something on wave function in quantum mechanics. I am thinking a situation if we have particles distributed over a periodic potential such that the wave function is periodic as well. For example, it could be a superposition of a series of equal-amplitude plane waves with...

Hi, I'm recently reading an introductory text about particle physics and there is a section about the Dirac equation. I think I can understand the solutions for rest particles, but the plane wave solutions appear to be a bit weird to me. For instance, when the upper states are (1 0), the lower...

If the problem is just to avoid negative probabilities, then why isn't the modulus of the value of wave function equal to the probability of finding the particle? I mean, is it proved by mathematics that the integration of the square of wave function value over a particular region is equal to...

Homework Statement frequency, Tension, mass, mode of vibration Homework Equations v = sqrt(T/μ) The Attempt at a Solution length of string is 2.14m weight .00247kg mass per unit length (μ) .00089 However, I need to confirm this graphically. I solved for mass per unit length μ = T/V^2 or...

In physics, wave mechanics and vibration specifically, do the terms note, tone and mode mean the same thing or do they refer to difference things? Also what does the mode of oscillation exactly mean?

Homework Statement Find the value of the RMS current in the following cases: (a) a sinusoidally varying current with a peak value of 4.0 A, (b) a square wave current which has a constant value of 4.0 A for the first 3 ms and -2.4 A for the next 2 ms of each 5 ms cycle, (c) an alternating...

We've learned Q&M in modern physics but I need to make sure I'm getting this concept right... So the photoelectric effect demonstrated the fact that a photon (wave) can knock an electron out of a metal, which could only happen if a photon was a particle. So much for photons being waves. I get...

Hello to everybody, I am solving some examples related to wave equation of shear horizontal wave in cylindrical coordinates (J.L Rose: Ultrasolic Waves in Solid Media, chapter 6), which is expressed as follows: ∇2u=1/cT2⋅∂2u/∂t2 The Laplace operator in cylindrical coordinates can can be...

There is also a classical model of a photon available, which to me explains a particular behavior of it. Can this model be proved to wrong ?

Lets say a state is defined by the minimal amount of independent variables to completely describe a system. One would come up with the (q,p)-phase-space for a point mass and as another example the Hilbert-space for quantum-states. Consider the very simple case of a standing wave in string...

Homework Statement Evaluate the Fourier Transform of the damped sinusoidal wave g(t)=e^{-t}sin(2\pi f_ct)u(t) where u(t) is the unit step function. Homework Equations \omega =2\pi f G(f)=\int ^{\infty}_{-\infty} g(t)e^{-j2\pi ft}dt sin(\omega _ct)=\frac{e^{j\omega _ct}-e^{-j\omega _ct}}{2j}...

Hi there, I am solving a second-order wave equation of the following form: ##v^2\dfrac{\partial^2 y}{\partial x^2} = \dfrac{\partial^2y}{\partial t^2}## where ##t## is time; ##y## is the wave function. I learn the wave function by assuming the system is linear and has a linear solution. The...

Homework Statement Is there a physical difference between the following wave functions? If yes, why? If no, why not? \Psi(x,0) =5e^{-ax^2} \Psi(x,0) =\frac{1+i}{\sqrt{3}}e^{-ax^2} \Psi(x,0) =e^{i\pi/7}e^{-ax^2} Homework Equations - The Attempt at a Solution They only differ in the...