Wave Definition and 999 Threads

  1. A

    Is the Photon Riding on an Electromagnetic Wave?

    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!
  2. L

    Find two lowest frequencies standing wave

    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...
  3. Docdan6

    Classical behavior, 3 dimension wave function and reflection

    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...
  4. D

    QM: The time evolution of a Gaussian wave function

    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}...
  5. P

    I Similarities / diffs between diffusion & wave propagation

    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...
  6. L

    How Do You Calculate Phase Difference and Equilibrium Timing in Harmonic Waves?

    Homework Statement the velocity of a harmonic wave in a strung-wire is 1550m/s and the wave's frequency is 740Hz there are two oscillators (?) in the wave called A and B such that B is 2m further ahead of A in the direction of the wave's travela) calculate the phase difference between A and B...
  7. M

    How the wave impedance of free space works?

    Hi All, what is the reason why very close to an electromagnetic source (Fresnel Region), the wave impedance Z0 in free space for electric field and magnetic field is not the same? Z0 for magnetic field increases and for electric field decreases by increasing the distance from the source...
  8. R

    B Particle or Wave? Duality Explained

    How anything can be a particle or wave at the same time.
  9. S

    A Change in the EM field energy due to dispersion of a wave packet

    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...
  10. B

    Question about Gaussian wave packet

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

    I Wave equation solution using Fourier Transform

    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...
  12. John Doe

    I Amplitude of particles in the medium of a longitudinal wave

    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...
  13. Theudius

    Does Frequency Change in a Medium?

    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...
  14. S

    B Wave particle duality - my visual/mental image

    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...
  15. Riverbirdy

    Finite difference Method of Wave Equation

    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...
  16. Debaa

    B Can You Really Observe a Wave Function Without Collapsing It?

    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?
  17. Ian Baughman

    Calculating Sound Intensity and Pressure Variation at a Distance

    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...
  18. J

    Finding the Group Velocity for Shallow Water Wave

    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...
  19. Toby_phys

    Mechanical wave reflection at a boundary

    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...
  20. W

    Behavior of an ultrasound wave on a particle

    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...
  21. T

    I Is the KleinGordon Eq the Wave Eq for Spin0 Scalar particles

    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
  22. Z

    Why wave function is probability of particle existence

    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...
  23. O

    I Doesn't wave duality for massive objects favor pilot-wave?

    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...
  24. Theudius

    What is the Relationship Between Interference and Wavelengths?

    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".
  25. E

    B LIGO: Detecting Gravity Wave Sources

    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...
  26. P

    A wave packet and a Delta potential

    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...
  27. T

    Traveling and Standing Wave Equations

    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...
  28. J

    Spring set makes up a traveling wave

    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...
  29. DrClaude

    European gravitational wave detector falters

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

    Eigenvalues and Eigenfunctions in Solving 2D Wave Equation in a Circle

    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...
  31. T

    Finding the Distance Between Sound and Wave Maxima at a Train Station

    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...
  32. P

    How Do Ocean Waves Shape Beaches?

    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...
  33. P

    Derive the wave equation for fields E, B from the potentials

    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...
  34. D

    How Does Time Affect the Displacement of a Plucked Violin String?

    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...
  35. ATY

    Kelvin Waves: How Do They Work and Why Do They Move Along the Coast?

    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.
  36. ThunderLight

    What composes the E Field of the Electromagnetic Wave?

    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...
  37. thecourtholio

    Using generating function to normalize wave function

    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...
  38. SunRay-dvsh

    A Why is the Matter wave analogous to photon and derived from it?

    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...
  39. qnach

    I Is Light a Particle or a Wave in Different Contexts?

    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...
  40. L

    Decreasing the distance between the wave sources....

    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...
  41. M

    B Double slit experiment wave collapse

    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...
  42. DeathbyGreen

    How to Derive u_k in Kitaev's 1D p-Wave Superconductivity Model?

    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...
  43. C

    Absorbing an electromagnetic wave

    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...
  44. Arup Biswas

    What are the properties of a wave?

    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...
  45. harini07

    Hooke's law and wave velocity related problem

    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...
  46. J

    Finding Density as a Function of Space and Time for 1D Wave Equation Problem

    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...
  47. M

    B Subsystem has no wave function

    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...
  48. FallenApple

    A photon vs an electron. Wave or particle?

    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...
  49. H

    Where to Stand in a Water Tank Experiment to Experience Minimal Wave Action?

    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...
  50. FreeThinking

    I Is entanglement severed by wave function collapse?

    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...
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