Read about waves | 262 Discussions | Page 1

  1. P

    Can someone give me a better intuition of bandwidth?

    Can someone give me a better intuition of bandwidth. The way I see it, is that the bandwidth is the range of frequencies which a signal/wave is allowed to have. This doesnt feel complete though. For example, how can I explain that TDMA, FDMA and CDMA are similar in this sense. As far as I know...
  2. P

    I How does a standing wave form?

    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?
  3. J

    Waves -- How does increasing tension affect frequency and period?

    Using this stimulation: https://phet.colorado.edu/sims/html/wave-on-a-string/latest/wave-on-a-string_en.html It looks like frequency is decreasing as I increase tension but online it says frequency increases as tension does. Also, Im unsure about what happens to the Period
  4. Frouel

    Harmonic motion and waves

    Solutions in a file.
  5. C

    Max velocity of a vibrating loud speaker membrane given sound intensity

    My attempt: p and T allows us to calculate ##Z=402 \frac{kg}{sm^2}## using ## Z=p*\sqrt(\frac{\gamma*M}{R*T})## . The sound intensity level at 10 meters allows us to calculate the intensity at 10 meters to be I=10``````^{-7} W/m^2 using ##50 = 10*log(I/I_0)##. Then, using the formula...
  6. 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...
  7. Vivek98phyboy

    I 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?
  8. 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...
  9. 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...
  10. danielhaish

    B 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...
  11. 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...
  12. G

    Power of a particle on a 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...
  13. 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...
  14. therealist

    How do I find the frequency, speed and direction of a wave

    Hey I am trying to learn how waves move in time and I am not sure how to solve the following question. Can someone please guide me through it.
  15. Diku Khanikar

    Waves and vibrations on a string

    Q.1. The length of a stretched string fixed at both ends has a length of l=10 cm, mass per unit length ρ= 0.01 gm/cm. If the tension ' T ' is produced by hanging a 11 kg weight at both ends of the string, then calculate, a) The wavelength of the first two harmonics, b) The speed of the wave...
  16. nuclearfireball_42

    Can I determine the phase angle of this equation by using the sin function?

    I've got the answer for (a). It's k = 0.78 N/m. I'm having problems with (b). I know that the equation of displacement in this case should either be : x(t) = Asin(ωt + φ) or x(t) = Acos(ωt - φ) where A = amplitude From what I understand, both the equation above should give the same result...
  17. K

    B How do orthogonal waves interfere?

    How do two highly directional, orthogonal light beams (or any other kind of waves) with the same frequency interfere with each other?
  18. M

    Formula for calculating wavelength of sound waves in interference?

    The values calculated was nowhere near the theoretical values, though I guessed they won't be as the results recorded was incredibly inaccurate. My teacher acknowledged the fact the final values won't be close to the theoretical ones but also said that my formula was wrong, that it works to find...
  19. Miles123K

    Wave behavior across two semi-infinite membranes with a special boundary

    Since the membrane doesn't break, the wave is continuous at ##x=0## such that ##\psi_{-}(0,y,t) = \psi_{+}(0,y,t)## ##A e^{i(k \cos(\theta)x + k \sin(\theta)y - \omega t)} = A e^{i(k' \sin(\theta ') y- \omega t)}## Which is only true when ## k' \sin(\theta ') = k \sin(\theta) ##. From the...
  20. L

    I How can a single slit diffraction create an interference pattern?

    I explained that Huygens principle states that each point on the wave front act as a point source which produces spherical waves which produce the interference pattern. Now his question is that where are these points and wouldn't there be infinite number of points on each wave front creating...
  21. S

    I Waves in 4D

    I am uncertain if this belongs in the differential geometry thread because I don't know what area of mathematics my question belongs in to begin with, but of the math threads on physics forums, this one seems like the most likely to be relevant. I recently watched a video by PBS infinite series...
  22. ContagiousKnowledge

    Normal modes of a rectangular elastic membrane

    Let's try inputting a solution of the following form into the two-dimensional wave equation: $$ \psi(x, y, t) = X(x)Y(y)T(t) $$ Solving using the method of separation of variables yields $$ \frac {v^2} {X(x)} \frac {\partial^2 X(x)} {\partial x^2} + \frac {v^2} {Y(y)} \frac {\partial^2 Y(y)}...
  23. F

    B Question about wave interference and coherence

    I have encountered the following definition of interference: Interference is a wave phenomenon in which two or more waves from coherent sources meet and superpose to form a resultant wave such that the amplitude of the resultant wave at any point is the vector sum of the amplitudes of the...
  24. A

    Find the Total Energy of the String

    Steps that I've taken: First, compute the derivative of the psi-function with respect to time and then take the square of the result Second, input the result into the KE integration formula. All that is left is to find the integrand, however this is where calculations became really "messy". It...
  25. Amartansh

    I Visualization of fields in waveguides

    Can someone provide me intuitive visualization of how E or H field can be longitudinal in a waveguide (TM/TE)? TEM is easy to visualize, but how EM wave can behave like sound in a waveguide (constant phase and amplitude plane in the same direction)? [Moderator: large bold font removed. In the...
  26. J

    I How do waves following a shockwave catch up to the shock wave?

    I was in an argument about a jet engine and I was arguing that since there is a cutoff in terminology what would kill someone approaching a engine is not technically sound, but a shock wave, (I'm probably wrong about this, but that's not the question). That got me wondering how waves can catch...
  27. Amartansh

    A Simulating forward electromagnetic scattering for a dielectric

    I want to simulate 2D TM scattered fields (microwave range) for austria profile. Austria profile has 2 circles beside each other of certain dielectric and one ring below the circles. So basically I have three dielectric objects in the domain of interest and also positions of Tx and Rx are known...
  28. nineteen

    How to find the frequency of the second wave?

    I don’t understand how to approach this. So I couldn’t make an attempt at a solution. Please help me understand better. Thank you in advance.
  29. novera

    Seemingly simple Physics 2 wave question (third harmonic frequency)

    I cannot find the correct answer anywhere online and the answer I keep getting is 5.4 (incorrect) Please show me the process to get to the answer! Thank you
  30. Miles123K

    Normal mode of an infinite spring pendulum system

    First I worked out the dispersion relations, which is pretty easy: ##M \ddot x_j = K x_{j-1} + K x_{j+1} - 2K x_j -mg \frac {x_j} {l} ## (All t-derivatives) We know ##x_j## will be in the form ##Ae^{ijka}e^{-i\omega t}## so the above becomes: ## -\omega^2M = K (e^{-ika}+e^{ika}-2)-\frac {g}...
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