Waves Definition and 1000 Threads

  1. E

    Signal Transmission Using Sound Waves

    Consider the following thought experiment... You are an engineer with a very peculiar assignment. With a mind to reduce the investment of excessive human labor and material waste, you have been asked to build an apparatus similar to an old-fashioned voicepipe. You are asked to ensure that the...
  2. P

    Evanescent Waves in near field for aperture > lambda (diffraction)?

    We have two different accepted formulas for the far field and near field respectively. I want a numerical program that works for both, furthermore I want to use it to calculate power through the aperture after confirming it in the far field vs near field. I start off by treating the far field...
  3. patric44

    The general equation of the superposition of orthogonal waves?

    hi guys i was trying to derive the general formula of two orthogonal waves $$x^{2}-2xycos(δ)+y^{2} = A^{2} sin(δ)^{2}$$ where the two waves are given by : $$x = Acos(ωt)$$ $$y = Acos(ωt+δ)$$ where ##δ## is the different in phase , i know it seems trivial but i am stuck on where should i begin...
  4. Mircro

    Radio waves in air and water - difference in path

    Hello, this is an assigment form the 4th grade high school physics in Croatia, concerning electromagnetic waves. Radio waves of wavelength 12m propagate from the source. The source is on the surface of the water and two waves propagate from it: one through the air and the other through the...
  5. Vivek98phyboy

    Reflection of inverted waves to form a standing wave

    Standing waves in a string fixed at one end is formed by incoming and reflected waves. If reflected waves are 180° out of phase with incoming wave, how could they combine to give an oscillating wave? Shouldn't it be completely destructive interference all the time across the whole length of string?
  6. Vivek98phyboy

    Contradiction in Phase of reflected sound

    While studying the fundamentals of sound waves in organ pipe, I noted that the fact about phase of reflected waves is contradicting while referring multiple sources This book of mine describes the reflection from a rigid surface/closed end to be in phase Whereas this one describes the...
  7. jaumzaum

    B Node Placement in Stationary Waves on Pool Surfaces

    Do stationary waves in a pool need to necessarily have nodes at the initial/final points where the wave hits the wall? I'm really asking this because the walls does not seem to be a physical blocker, like a fixed end of a rope that is tied. Considering friction I would say that some energy...
  8. ComradeConrad

    I Gravitational waves as not "proximal"?

    Usually spacetime curvature is localized/proximal to what is "causing" it, right? I'm wondering whether there is a term for the situation seen with gravitational waves where there is some relatively flat space between observable gravitational effects and the mass(es) that "caused" them? I'm...
  9. W

    Understanding Standing Waves in Open Tubes

    Hello everyone. I'm having some trouble understanding waves. Particularly standing waves in an open tube. So we have an open tube, someone blowing air into it creating a first harmonic and we have particles oscillating back and forth. The particles oscillating pressurize where the air...
  10. JayJ

    I Why does energy travel in waves?

    Hi all- Im new. Had a weird thought and when researched I only found the answer of bc that’s how we observe it. question. Why does energy travel in waves? Bc that’s how we see it? can anyone explain to me why energy moves in waves and not a straight line? Thanks to all who help me rid...
  11. greg_rack

    Parameters and the nature of electromagnetic waves

    By rearranging over and over ratio formulas involving frequency, speed and wavelength, I came up with the equation: fP/fQ=10^-8xVP/VQ This led me to take into account only rows A, B, E, and F... but I can't really understand which one of these is the right one.
  12. K

    I Gravitational Waves: Hardest GR Topic?

    Is the subject of gravitational waves the most difficult one to grasp on the theory of Relativity? Or is it just the math that is very complicated?
  13. F

    Exactly how do pressure waves work at the molecular level?

    I've searched high and low for an answer to my question and I can't find a thing. Let's say I blow into the end of a tube. The opposite end is connected to a reed; when the air hits the reed, the reed vibrates and I can hear a sound. The harder I blow, the louder the reed sounds. I've tested...
  14. Haorong Wu

    Prove that phase-conjugate waves satisfy Maxwell's equations

    This is the second part of a problem. In the first part of the problem, I have proven that ##\mathbf E^* =\mathbf E_0^* ( \mathbf r) e^{i \omega t}## satisfies the Maxwell equations. Then, in this part of the problem, I tried to first prove that ##\mathbf E^{'} =\mathbf E_0 ( \mathbf r) e^{i...
  15. Nick tringali

    I Waves and phase shifts (attempting to learn physics)

    So I haven't taken a physics class in 4 years and forgot a lot about it. I am trying to understand an article but I am stuck on a core concept "Because essentially no amplitude reduction of the light occurs to create contrast and because the phase delays are usually very small, the generation of...
  16. L

    I Quantum Measurements with Gravitational Waves

    Would using gravitational waves to measure (it's obviously a gedankenexperiment!) position and momentum of, say, an electron in a specific state, disprove HUP since the quantum of energy of grav. waves does not exist? Would it be possibile to have an arbitrarily small uncertainty in position...
  17. R

    B Gravitational Waves: Impact & Effects on Gravity

    When a gravitational wave passes through a location in space, what is the magnitude of equivalent gravity that it produces at that location? Or rather, is it correct to say that gravity can influence gravitational waves but gravitational waves can't influence gravity?
  18. T

    Amplitudes of longitudinal sound waves

    I'm coming back to physics after a long so apologies if this has a basic answer- How can the amplitude of a longitudinal sound wave be increased without increasing its wavelength? I understand what it would look like graphically if a low amplitude sine wave and high amplitude sine wave were...
  19. V

    B Do physical (macroscopic) waves consist of matter?

    When I think of a wave propagating through space I think of a geometric wave-like structure propagating through the matter in the surrounding environment. If someone yells and you hear their voice is it actual matter that is emitted and that your ears pick up on? If this were the case there...
  20. Redbelly98

    Insights Intro to Physically Reasonable Waves on a String

    [url="https://www.physicsforums.com/insights/physically-reasonable-waves-on-a-string/"]Continue reading...
  21. LCSphysicist

    Standing waves on a string -- Find the difference of phases

    The immediate thing i did here is ## \Delta \varphi = k(\Delta x) ## Interesting enough for a topic, if you use this equation you end up wrong like me, the answer is not D. Not sure what is the problem.
  22. R

    B Measuring Gravitational Waves w/ Elevator Accelerometer

    An elevator in outer space where there is negligible gravity, accelerates at the most precise constant acceleration that current technology enables. Inside that elevator, resides an accelerometer that is the most precise accelerometer that current technology enables, but not more precise than...
  23. R

    B Gravitational Waves: A Question on Earth's Magnitude & Frequency

    Here is a video i have watched: It made me think of the following questions: A. Gravitational waves at the scale that emanate from earth: 1. It is doubtful if they exist at all. 2. They are predicted to exist, but at an extremely small magnitude. B. In case the answer is A2: 1. These...
  24. T

    B Gravitational Waves in Positively Curved Universe?

    Hello everyone! I was listening to a podcast that featured a cosmologist and she mentioned that if the universe was positively curved (and therefore a sphere overall), light would travel around the universe and then end up where it started. I wondered, would a gravitational wave do the same?
  25. Remixex

    Contour integration around a complex pole

    $$\int_{-\infty}^{\infty} \frac{e^{-i \alpha x}}{(x-a)^2+b^2}dx=(\pi/b) e^{-i \alpha a}e^{-b |a|}$$ So...this problem is important in wave propagation physics, I'm reading a book about it and it caught me by surprise. The generalized complex integral would be $$\int_{C} \frac{e^{-i \alpha...
  26. danielhaish

    Do two light waves with difference frequencies connect when they meet?

    for example the blue light wave have frequency of about 450Thz and the yellow wave have frequency of about 508thz (I found this data in the internet) , so if this two wave would get closer to each other we would observe them as green wave which have frequency of 526Thz . so my question is...
  27. M

    I Vibrations of waves with pinned vs free boundary conditions

    Hi PF! Can someone explain to me why in math/physics the frequencies associated with waves (or say drum heads) tend to be larger when the boundaries are pinned as opposed to free? If possible, do you know any published literature on this? Thanks!
  28. B

    Classical Opinions about these textbooks for vibrations and waves

    Hi. I am going to enter uni this October as a first year physics major.One of the first courses I will take is Vibrations and Waves,and the recommended materials are as below: French,Vibrations and Waves Pain,The Physics of Vibrations and Waves, 6th Edition According to Amazon's review,there...
  29. LCSphysicist

    Problem with reflection and transmission of waves

    See, to illustrate: Let's suppose there is an incoming wave by x < 0, what is the problem? It will find a bead in the string, so: , x < 0 , x > 0 T and R are the transmitted and reflected coefficients. Now suppose there is another bead in x = L. The problem is what happens 0 < x < L: The...
  30. aspodkfpo

    Sound waves affected by wind/sound waves in materials

    Are sound waves in air affected by wind? If the medium of the air propagation travels forward, does the sound also travel faster or is the sound simply vibrations in positions of space which disregard the movement of its medium. Would a transverse wave similarly move faster? If I was to...
  31. B

    What is the resultant frequency if two similar waves superpose?

    for a) I have ##v = \lambda f= \frac{\omega \lambda}{2 \pi}## for c) and d) I denote ##\frac{2\pi}{\lambda_1} = k_1## and ##\frac{2\pi}{\lambda_2} = k_2## assuming ##k_1 > k_2##. so using the triangular identity I got $$y_1 + y_2 = 2A cos(\frac{k_1+k_2}{2} x - \frac{\omega_1 + \omega_2}{2} t)...
  32. LCSphysicist

    How do we combine two waves to create Lissajous figures?

    To answer (a), i imagineed the oscillations parallels (say to z), so we simply add ξ1+ξ2 for b, i imagined two vectors ortogonais, representing the oscillations, so we should add √(ξ1² + ξ2²), is this right?
  33. jaumzaum

    I Stationary waves in a vertical rope

    I was wondering if we could produce stationary waves in a vertical rope. There is a nice result we can get from a vertical rope that the pulse created from the lower extremity travels upwards with acceleration g/2 and the pulse created in the upper extremity travels downwards with acceleration...
  34. S

    Must the limits on the propagation speed of waves refer to a media?

    An example (I think) of creating a phenomena that appears to propagate faster than the speed of light would be to have a line of people holding flashlights and giving each person a schedule of when to blink his light. With proper schedule we could create the illusion that point of light is...
  35. R

    B Detecting Gravitational Waves: Earth-Like Planet Possibility

    Is it theoretically possible that one day a gravitational wave detector will be developed, that is sensitive enough to detect gravitation at the order of magnitude that an Earth like planet has?
  36. L

    Multiple-Choice Questions on the Behaviour of Waves and Light 😁

    Question 1; The conditions for total internal reflection are: -That light is traveling from an optically denser medium (higher refractive index) to an optically less dense medium (lower refractive index) - That the angle of incidence is greater than the critical angle. Therefore, I conclude that...
  37. LCSphysicist

    Solving Waves on a Metal Rod with kx + Φ

    I am trying to solve this question by ξ = A*cos(ωt + θ)*sin(kx + Φ) Anyway, the two initial terms of the product helps nothing (i think), what matters is sin(kx + Φ) So, i tried by two ways: First: The stress is essentially zero on the ends, that is, something like cte*∂ξ/∂x (strain) would be...
  38. Abdullah Almosalami

    Question about Waves on a String

    Summary:: Could you send a second wave pulse down a string that would overtake an earlier wave pulse? Got this question in my physics textbook. Ignoring reflection (i.e., you had a very long string), say you send a transverse wave pulse down a string fixed on its other end to a wall. Could you...
  39. LCSphysicist

    Equations for the velocity of progressive travelling waves

    Someone know how to derive v = √(T/μ) for waves traveling? (without being by dimensional analyse)
  40. C

    Frequency of EM waves produced by linearly accelerating charges

    I was wondering about EM waves produced by linearly accelerating charges, as opposed to oscillating charges. With oscillating charges, the frequency of the wave depends on the frequency of the oscillation of the charge. But what determines the frequency of the wave produced by a linearly...
  41. danielhaish

    I Are there waves that go up and down without going below zero displacement?

    weave is change in something. and I always see harmonics wave that looks like this there is some normal value let's say the height of the water then the height of the water become higher then normal and then lower like that But do there are an harmonics waves in physics that just going up and...
  42. J

    Calculating the amplitude of waves in water

    Suppose I have a perfectly circular pool which is four meters in radius, two meters in depth, and filled with water. Say I drop a steel ball with a radius of five centimeters into the middle of the pool from a height of five meters above the water's surface. After three seconds, what will be the...
  43. ?

    Reflection and transmission of waves in a medium of nonuniform density

    Hello all, Apologies in advance for the text-wall; this is a rather involved question. I am trying to compute the effective transmission coefficient for a medium of non-uniform refractive index. For simplicity I am assuming the slab has thickness ##d##, that ##n(0)=1##, and that ##n(d)=n##...
  44. mliempi2018

    An interesting coupled oscillators problem (multiple springs and masses)

    I need to find the differential equations for each mass. ##y_1## is the equilibrium position, and ##y_2## is the second equilibrium position for each mass. I was thinking consider the next sistem: \begin{eqnarray} k\Delta y-mg&=&m\frac{d^2 y_2}{dt^2} \\ -2k\Delta y_1 -k\Delta y_2 -2mg...
  45. pelinkovac

    I Gravitational Wave Creation: Is a Stationary Wave Possible?

    Hello, Apart from the graviton postulate, which would permit such a mechanism, my question is: would a similar mechanism be possible with a stationary wave? (the simplest scenario I can immagine is of two opposing waves). My background is in DSP and Acoustics so I might get things wrong (a...
  46. G

    Why is the power of a particle on a wave zero in a stationary wave?

    I've marked the right answers. They mainly indicate at power carried by the particles being zero, and here is my doubt- why should it be zero? Shouldn't it have some definite value? I do understand that the kinetic energy is max at the y=0 and potential energy is max at y=A, but I don't know...
  47. P

    B Consequences of the Existence of Gravitational Waves?

    I'd like to see some of the consequences of the existence of gravitational waves (both expected and unexpected), in laymen's terms so a simpleton like me can understand and relate to them. A possible consequence that I thought of (and I'm sure someone will correct me if I'm wrong) is that...
  48. loophole

    Water deformation subjected to ultrasound waves

    Hello everyone, in one of my projects I am dealing with the following problem: We have a tank filled of water. If we assumed that a focused ultrasond beam hit the water perpendicularly to the surface. How can I calculate the displacement of the water surface? In particular, I am interested in...
  49. jaumzaum

    Why can shock waves condense water vapor?

    Why can a shock wave condensate water droplets in the air and produce the visible vapor cone that we see when objects move faster than the speed of sound. Also, does this condensation happens only when the object is moving with a velocity greater than sound velocity? I don't understand the...
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