Wave Definition and 999 Threads

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...

Say I have a disk spinning in a buoy. Let me say the spin axis is vertical to the flat surface of the buoy (or sea if there were no waves). Now along comes a wave (that will induce a "precession" of the disk/buoy. The axis of this precession is from "starboard to port." This would induce...

I am studying about the cavity radiation inside a metallic cube. In the textbook it states that there are two independent waves corresponding to the two possible states of polarization of electromagnetic waves. What does it mean by this? (My current assumption is the phase change of the waves)...

Suppose we have a particle, let's say an electron, in a box of size D. And we add another one next to it at some distance L center to center. How do we solve for the wavefunctions of the electron. Can it be solved in normal QM or do we need QFT. Thanks.

Would it be possible to transmit information through gravitational waves? It must be a giant leap for mankind if we can utilize gravitational waves for communication since the electromagnetic spectrum for communication is a scarce resource and not much space is left. I imagine that the...

In the picture about, I gave 1. a picture of a segment of string for reference, 2. a description of the driving force and 3. a description about the potential energy per unit length of a point in the wave. I have two questions here. 1. Why does the driving mechanism produce a force to balance...

Hi, I am new to the Pilot Wave theory. In my understanding this theory gives a hope for reconstruction of the realism. But I have several maybe naif questions. What is the wavelength of the pilot wave? Is it the same as deBroglie wavelength formula? Very often people use the walking droplets...

Hi Guys, I have attempted to solve the following question and was hoping someone can have a look and give some feedback. Any help will be greatly appreciated. Thanks! 1. Homework Statement Angler fish emit light through bioluminescence. An angler fish is swimming in a fish tank that has a...

Homework Statement λ = 3m T = .5 s k= 2π/λ = 2.09 radians/m ω= 2π/T = 12.56 = radians/sec v = ω/k = 6m/sec At π radians with sin wave x = 3m At 5π radians/6, x = 2.48 m t = 2.48m/6m/sec = .41 sec What is y at x,t At t0 x = t = 0 [/B]Homework Equations y = Asin(kx-ωt)[/B]The Attempt at a...

Homework Statement Given the following expression $$ \Psi(x,t) = A cosh(36 x^2 - 12 x t + t^2)$$ Determine whether this is a traveling wave and if so what is its propagation velocity and propagation direction? Homework Equations Wave equation $$ \frac {\delta^2 \Psi(x,t)} {\delta x^2} =...

If there is a net force along the y-axis, i.e. T sin(θ2) - T sin(θ1) Why is it equals to ma, where a is the acceleration of the piece of string along the y-axis? Shouldn't there be a torque so the piece of string rotates? Sorry for sounding stupid.

Hi everyone, I'm reading about the solution of the wave equation in free space on Stratton - Electromagnetic Theory and Snider - PDE and I got a little confused. The wave equation in 3D (plus time) is the following $$\frac{\partial^{2} \Psi (x,y,z,t)} {\partial t^{2}}=\nabla ^{2}\Psi...

Homework Statement Given the wave function Ψ(θ,φ,r)= f(r,θ)·[cosφ+cos2φ-i(senφ+sen2φ)] for an electron. (φ is the azimut) -Does it spin arround the z axis? -What kind of polarization has? It is dextrogyre or levoryre? -What are the posible values of Lz and what are they respective...

Hi everyone! I'm a psychologist form Brazil, so sorry for the bad English and for the lack of knowledge in math! I ve been trying to understand the Schrodinger equation and, as predicted, it's very hard! Please, help me with this: A sine wave function can be written as: F (x) = sin (x) And...

Homework Statement Show that the normalized wave function for a particle in a three-dimensional box with sides of length a, b, and c is: Ψ(x,y,z) = √(8/abc) * sin(nxπx/a)* sin(nyπy/b)* sin(nzπz/c). Homework Equations Condition for the normalization: ∫0adx ∫0bdy ∫0cdz Ψ*(x,y,z)Ψ(x,y,z) = 1...

When why sey that light is electromagnetic wave i understand this. But what i do not understand is where photons come into picture ? can somebody explain me the relationship between those two . My knowledge in this respect is not great so I would ask that the answers be adjusted .

Homework Statement Homework EquationsThe Attempt at a Solution ## v = \frac { \omega } k ## ## \omega = \sqrt{ kg \tanh (k) } ##I have no idea to guess the graph. I put g = 9.8 and tried to calculate ## \omega ## for different values of k. ## \omega (0 ) = 0, \omega (30) =...

Take a wavefunction ##\psi## and let this wavefunction be a solution of Schroedinger equation,such that: ##i \hbar \frac{\partial \psi}{\partial t}=H\psi## The complex conjugate of this wavefunction will satisfy the "wrong-sign Schrodinger equation" and not the schrodinger equation,such that ##i...

Homework Statement An electromagnetic wave is incident on a surface which absorbs all the electric field. Use Maxwell’s equations to determine the magnetic field on the other side of the surface. Homework Equations The Attempt at a Solution My initial thought was that ##B=0## as a varying B...

Homework Statement Note : There are no minus signs in first two options . Homework EquationsThe Attempt at a Solution The wave is propagating in +z direction whereas the electric field is varying in x direction . On reflection , there is a phase change of π . Also wave starts traveling in...

Hi! I would like to Start from Maxwell's equations in order to solve the wave equation analytically for oblate and prolate spheroids. Could you suggest me any help?

https://i.hizliresim.com/ZO0bvG.jpg I don't understand that where ε0/ε is coming from? Can you explain this?

What is the polarization of the following wave? E = (x 20∠0 + y 20∠90°)e-j3z, where x and y are unit vectors I haven't been able to make an attempt because i have no idea how to start and none of the equations i got in class seem to apply. I know that polarization refers to the direction that...

1. Problem Statement Find the steady state output yss(t) for the input u(t)=t-π in terms of an infinite sum of sinusoids. We are given the transfer function as: 2. Homework Equations G(i) = ... |G(ik)| = ... Φ(ik) = ... (this is the angle) yss(t) = βk||G(ik)|ei(kt+Φ(ik)) ***check that this...

In Griffiths fourth edition, page 413, section 9.4.1. Electromagnetic Waves in Conductors, the complex wave number is given according to equation (9.124). Calculating the real and imaginary parts of the complex wave number as in equation (9.125) lead to equations (9.126). I have done the...

Me and my friend have recently (half a year ago) had a huge debate, between ourselves, about the wave-particle duality. We took sides in light being a particle or a wave. I was for particle he was for waves. At the end of a hot-filled week of arguing, the debate ended up with the acceptance of...

Homework Statement A string of length L is fixed at both ends ##u(0,L)=u(L,t)=0## The string is struck in the middle with a hammer of width a, leading to an intial condtion ##u(x,0)=0## and $$U_t(x,0)=v_0 $$ for $$\frac{l}{2}-\frac{a}{2} \leq x \leq \frac{l}{2}+\frac{a}{2} $$ and...

Homework Statement An E field with f = 2.45*10^9 Hz passes through a material with the following properties e_r = 10 u_r = 1 sigma = 1 (S/m) The Incident E field has peak magnitude of 300 V/m at the air to surface boundary. (a) *solved* Find the incident power density at the material...

Hi, I have two questions about the solutions to Maxwell’s wave equations: 1. I always hear that E and B must be in phase. Why is this, mathematically? And wouldn’t this also be a solution: By=B0sin(kz)cos(wt) Ex=E0cos(kz)sin(wt) In which case E and B are out of phase. 2. In a vacuum with no...

Hello everyone! :-) Actually I'm starting to understand acoustics physics and I figured actually out about this equation: $$\frac{\partial^2\psi}{\partial t^2}=c^2 \nabla^2 \psi$$ which describes practically about pressure and propagation speed into space and time. I know also this equation...

Dear all Something is bugging me. I hope you can help. I read in texts that if f(t) = sin(t) then the period of the function is the time taken (secs) to complete one cycle. I also read in texts that if f(t) = sin(2t) then the period of the halved. No problems here. I see that (2*t) = (omega*t)...

I read in Griffith's quantum mechanics that in a particular system, the second time measurement of the position (say) would yield the same result (the same collapse or the same spike)given that the measurement is done quickly (since it soon spreads out). I don't understand how quick this is...

Homework Statement The electric guitar radiates very little sound directly, but instead relies upon pick-ups (transducers) placed beneath the strings. Establish, showing clearly how you reach your answer, which harmonics of the open string you are likely to observe if the pick-ups are placed...

Homework Statement Homework Equations If i solve the wave equation using separation of variable and laplace tranform. Will i get the same answer ? The Attempt at a Solution

I wonder if it is possible to generate a propagating EM wave by making a single charge oscillate in vacuum ? In practice, when we create EM waves, we (always ?) have opposite charges oscillating, like with a dipole antenna : In the dipole antenna case, I can see how the fields detach...

Dear forum members, I'm wondering about the physical meaning of the imaginary part of a complex wave number (e.g., the context of fluid dynamics or acoustics). It is obvious that w = \hat{w} \mathrm{e}^{i k_z z} describes an undamped wave if k_z = \Re(k_z) and an evanescent wave if k_z =...

1. Homework Statement I've been using a recurrence relation from "Adv. in Physics"1966 Nr.57 Vol 15 . The relation is : where Rnl are radial harmonic oscillator wave functions of form: The problem is that I can't prove the relation above with the form of Rnl given by the author(above). I've...

http://imgur.com/cUNs2z7 In this book I found by chance on Google, the author claims that “solutions of the wave equation only take the form of functions (...) in one and three dimensions. In two dimensions solutions are more complex”. Then, at the end of the paragraph of interest (which I...

I'm puzzled that the stretching of space by a gravitational wave stretches the LIGO arm but not the light within it. Because we are told that the red shift of a distant galaxy is caused by light being stretched by the expansion of space (the universe).

Hello, There are many different wave equations that describe different wave-like phenomena. Being a differential equation, the WE is a pointwise relation and applies to the wavefield at spatial points. The equation is homogeneous when the source term is zero. That means that the solution...

I'm trying to figure out what happens to a tension-ed anchor line when encountered by a surface wave (transverse and longitudinal ) Assuming a 2 dimensional view, or that the cable is sufficiently wide that the wave cannot go 'around it' what happens to the path and speed of the surface wave...

In a half wave rectifier only a single diode is present. One end of the secondary wire of the transistor is connected to the p side of diode while the other to the load resistor. The n side is connected to the load resistor. When the diode is reverse biased no current passes through it. But...