Wave Definition and 999 Threads

Homework Statement A radio speaker produces sound when a membrane called a diaphragm vibrates, as shown above. A person turns up the volume on the radio. Which of the following aspects of the motion of a point on the diaphragm must increase? a) the max. displacement only b) the average...

I collected this data by moving a sound level meter slowly through a total length of 0,75 meter between two speakers pointing towards each other. The wavelength of the sine waves was 0,343 meters and the frequency was 1000 Hz. The sound level meter measured the sound in dbA 20 times a second...

Why the velocity of longitudinal wave in solid is greater than transverse wave

Find the wave equation U(x,t) of a vibrating string with linear density d, tension p, initial velocity zero, weight L and initial displacement U0(x) = a1*sin(2*pi*x/L)+a2*sin(4*pi*x/L). Guys, please help me with this task. I did the following procedure: The U(x,t) solution must me a sum of...

<Moderator's note: Moved from a technical forum and thus no template.> I've done an experiment on standing waves on a string. By graphing √T vs λ (where T is tension and λ is wavelength) using the linearized equation √T = (1/√μ) f ⋅ λ, I was able to get this data: μ = .000256 kg/m slope = 1.78...

Hope, I do not violate any forum rules here, this is not a discussion topic, mostly. I am just asking for help looking for a specific article/work. I just remember reading somewhere that there is a QM theorem or article saying smth. in a sort that if the same physical "ontic" state would be...

For the harmonic oscillator, I'm trying to study qualitative plots of the wave function from the one-dimensional time independent schrodinger equation: \frac{d^2 \psi(x)}{dx^2} = [V(x) - E] \psi(x) If you look at the attached image, you'll find a plot of the first energy eigenfunction for...

I am having a problem with understanding concepts related to the speed of a wave. Here are my thoughts laid out: 1) The speed of a wave is dependent only on the medium 2) When a wave crosses from a less dense medium into a more dense medium (or visa versa) the speed of the wave is always...

Hello, Came across https://drive.google.com/file/d/1bpB7BcVf1yQLiwg9quAn2vlhu8-i6Zy_/view and I'm not sure about one thing For the 2 parts of the equation with sin, is it: 1. [...sin(kx)]sin(wt) or is it: 2. [...sin(k)*x]sin(w)*t Thank you -DR

Homework Statement I have a simple problem relating to the superposition of plane EM waves that I'd to try out using complex notation. Could anyone run through the work to see if my understanding is right? Many thanks in advance! The incident E bit of the wave is $$\vec{E}_I = E_0 \sin(ky -...

A subatomic particle can either be a wave or a particle. When it is a particle, what actually is it? is it literally like a tiny physical ball rattling around? (If not, then what is it?) And when it is a wave, what is it? From my understanding, when a particle behaves like a wave, the...

Hi guys I am having trouble determining a quite spot based on where you stand in respect to distance from the speakers. I have solved the question below but I need someone to explain to me how the "n" value can be used to determine a quite or not-quite spot. Am I looking for whole numbers? If n...

Homework Statement A 1.2 m tube is closed at one end. A stretched wire is placed near the open end. The wire is 0.330 m long and has a mass of 9.6 g. It is fixed at both ends and oscillates in its fundamental mode. By resonance, it sets the air column in the tube into oscillation at that...

Homework Statement An EM wave from air enters a medium. The electric fields are --> ^ E1 = E01 cos(2πv(z/c-t) x --> ^ E2 =E02cos(k(2z-ct)x in a medium ,where the wave number k and frequency v refer to their value in air.the medium...

Homework Statement Discuss the concept of the wave-particle duality for electrons and photons and include an equation which connects the wave like and particle like properties. Homework EquationsThe Attempt at a Solution So I am having trouble with how to word this question and generally...

Homework Statement Show that the displacement D(x,t) = ln(ax+bt), where a and b are constants, is a solution to the wave function. Homework Equations I'm not sure which one to use: D(x,t) = Asin(kx+ωt+φ) ∂2D/∂t2 = v2⋅∂2D/∂x2 The Attempt at a Solution I'm completely lost on where to start...

Let us look at short segment of a rod with its length dx. Due to longitudinal wave, left endpoint moves for s in the direction of x-axis and the right endpoint moves in the same direction for s+ds. Because I want to calculate the elastic energy of the wave motion, I need the extension of dx so...

Why is it that bosons (particles having symmetric wave functions) have integral spins and fermions (particles having antisymmetric wave functions) have half integral spins? A lot of books state this without specifying the reason. I was wondering if this is a theoretical deduction. Or is it an...

Hi, I'm doing a very simple problem, but I don't understand the diagram provided (see image below). What is m here? I know that m is the order with respect to the central bright fringe, but there isn't a central bright fringe (assuming those circles are the bright fringes)? Homework...

Hi all! I am doing an experiment where we create a standing wave by attaching a string to a hanging mass at one end and to a string vibrator at the other (the string passes through a pulley). When plotting the graph, the slope is inevitably 1/(u*f^2) where u is the linear density and f the...

Hi. I'm following the "derivation" in some lecture notes which shows that the Electric and Magnetic fields are perpendicular to each other and to the direction of propagation. There are 2 points I don't understand A solution to the wave equation for E-fields is given as E = E0 exp i(ωt-kz). It...

Homework Statement Two long strings P and Q ,each having linear mass density 1.2 x 10^-2 are stretched by a different tension 4.8 N and 7.5 N respectively and are kept parallel to each other with their left ends at x=0.Wave pulses are produced on the strings at t=0 on string P and at t=20ms at...

Homework Statement y(x,t)=0.8/{(4x+5t)^2+5 }represents a moving pulse,where x and y are in metre and tin second.Then choose the options. (a)Pulse is moving in positive X axis (b)In 2 secs,it will travel a displacement of 2.5m (c)It's maximum displacement is 0.16m (d)It is a symmetric pulse...

The wave equation in one space dimension can be written as follows: .A traveling wave which is confined to one plane in space and varies sinusoidally in both space and time can be expressed as combinations of What is the difference between these two wave equations?? And is traveling wave always...

Homework Statement The question is as follows: The distance between the two positions of maximum loudness is x What is the wavelength of the sound emitted by the tuning fork ? A. x/2 B. x C. 3x/2 D. 2x the correct answer is answer D. Homework Equations Pipe with two ends open λn=...

Homework Statement The correct answer according to answer sheet is answer B. Homework Equations λn= 2L/n (both ends open) λn = 4L/n (one end open one end closed) c=λf Speed of sound does not change. as it is still in air... (correct assumption? ) The Attempt at a Solution f1= 500Hz L =...

I know that Maxwell discovered that a disturbance in the electromagnetic field propagates at the speed of light - which Occam's razor would say that light being such a wave would explain it - but not definitively that that is true (e.g., gravity waves, or at least at that time in history, some...

Is there a machine that can emit multiple radio waves simultaneously? I am trying to create a demonstration, but it requires multiple radio waves at once and cannot find any machines that can do so.

Homework Statement Consider a harmonic wave given by $$\Psi (x, t) = U(x, y, z) e^{-i \omega t}$$ where ##U(x, y, z)## is called the complex amplitude. Show that ##U## satisfies the Helmholtz equation: $$ (\nabla + k^2) U (x, y, z) = 0 $$ Homework Equations Everything important already in...

Homework Statement Consider a harmonic wave given by $$\Psi (x, t) = U(x, y, z) e^{-i \omega t}$$ where ##U(x, y, z)## is called the complex amplitude. Show that ##U## satisfies the Helmholtz equation: $$ (\nabla + k^2) U (x, y, z) = 0 $$ Homework Equations Everything important already in...

Suppose a ocean wave encountered a section of ocean which had a higher level of aeration from gas such as methane escaping from the seafloor. Due to the aerated sections apparent lower density would the wave travel slower through the aerated section than its propagation speed thru pure seawater ?

Homework Statement How can I estimate the decay coefficient in Ae^-at for this graph I know the equilibrium position Homework Equations damped oscillation The Attempt at a Solution not sure if this is right.[/B]

I continue to be occupied with the first chapter of Lessons on Particle Physics by Luis Anchordoqui and Francis Halzen. The link is https://arxiv.org/PS_cache/arxiv/pdf/0906/0906.1271v2.pdf. I am on page 24, where they derive equations 1.5.67, which are: ##(\gamma^\mu p_\mu-m)u(p)=0## and...

Homework Statement I didn't quite understand my professor when he defined the speed of longitudinal wave. Lets say I have a slinky and on one side we act with a force F along the slinky. Well, he said that this part then starts to move with velocity v. But how? v isn't constant... Homework...

Hello, Many Researchers talked about the following parameters: 1. Propagation length of the surface plasma wave(spw). 2. penetration depth of surface plasma wave(spw). 3. concentration of the (spw). 4. the equation of the interface in vacuum - plasma interface. I feel confused regarding such...

Hi. I am working through " A Student's guide to waves " by Fleisch. In deriving the wave equation for a longitudinal wave it uses dψ = (∂ψ/∂x) dx where ψ is the displacement but ψ is a function of x and t ; so shouldn't this equation be dψ = (∂ψ/∂x)...

Homework Statement A hand induces a transverse wave in a string by periodically moving up and down. This causes the string to move up and down. This movement propagates through the string producing a series of wavefronts which move towards the fixed wall with a velocity v. How do we...

Homework Statement : [/B]This is a general conceptual doubt, not a numerical based doubt. We were taught that when an electron(or any charged particle) moving with uniform velocity enters a magnetic field(perpendicular to its direction of motion), then a force acts on the electron which makes it...

I am continuing to work through Lessons on Particle Physics. The link is https://arxiv.org/PS_cache/arxiv/pdf/0906/0906.1271v2.pdf I am on page 22, equation (1.5.58). The authors are deriving the Hermitian conjugate of the Dirac equation (in order to construct the current). I am able to...

Homework Statement I experimented with standing waves on an oscillating string, and I was asked to calculate the absolute error of µ (linear mass per unit length). I don't know how to calculate it, so please help me. I loaded 100g, 200g and 300g on the string. Below are tabulated data of the...

Homework Statement I am being asked to show that the wave function ψ and dψ/dx are continuous at every point of discontinuity for a step potential. I am asked to make use of the Heaviside step function in my proof, and to prove this explicitly and in detail. Homework Equations...

In reading about the photoelectric effect I noted that frequency accounts for the energy of the photon which must be high enough to liberate free electrons and the amplitude is the cause of intensity.Now, how can the amplitude be responsible for more than the liberation of more than one photon...

i was desigining a simple ( simple as in no MPPT) PV-pump standalone system, and we decided on using an AC-pump, so while i was searching for inverters i noticed the remarkable difference in price ranges, so i started to read about the difference between the two, so far the disadvantages of the...

Homework Statement A wave pulse on a string is given by D(x) = D[0][/SUB]/(x[2][/SUP]+a[2][/SUP]), where D0 is a constant with units of cm3 and a is a constant with units of meters. a. If the wave moves along the string at a velocity of v in cm/s, what is the transverse velocity of particles...

Hi, I have read some on the PDEs for fluids, and particularly for rogue waves, where for instance the extended Dysthe equation and the NLSE look rather intimidating: Take for instance the Non-linear Schrödinger eqn: \begin{equation} \frac{\partial^2 u}{dx^2}-i\frac{\partial d...

Hi. If I know the pitch and amplitude of a sound wave, will I be able to calculate its volume. I can understand volume of devices vary betwerb brands and other categories. For the sake of discussion, let's assume volume to be a consistent unit or if db is the right unit, let's take that.

Hi, I have been looking in various text about how to find an admissible solution to the Schrödinger eqn in one dim. in the harmonic oscillator model. As in MQM, the solutions to this are said to be ##Ae^{ikx}+Be^{-ikx}##, which are then said to be not admissible. The book then goes straigtht to...

So we have the focal lengths: f1, f2, ..., f7 = 25mm And the distance between the lenses: d1-2, d2-3, ..., d6-7 = 50mm I have figured out that if the system would be afocal if it had an even number of these lenses. This is because the focal length of two adjacent lenses is the same as the...

Homework Statement When a guitar string is stretched to have a tension T, it produces a frequency f. You change the tension by a very small amount ∆T . Show that the new frequency of the guitar string is fnew = f ( 1 + (delta T)/2T) For example, a guitar string has tension T = 10N and...

Homework Statement I am actually following the derivation of the wave equation from Maxwell equations. And I do not understand one step, because in the task for the derivation I get a slightly different result (maybe they are equivalent, but I am not sure). Homework Equations In the attached...