Waves Definition and 1000 Threads

Homework Statement Use Maxwell's equations to elaborate an coherent explication of why electromagnetic waves propagate independently of the source that produces them. Homework Equations Maxwell's equations in vacuum: ##\nabla * E=0## ##\nabla * B=0## ##\nabla \times E = -\frac{\partial...

Please, can anyone explain how formula (5) is obtained in J.J. Barton article ''Approximate translation of screened spherical waves" . Phys.Rew. A ,Vol.32,N2, 1985. ? https://doi.org/10.1103/PhysRevA.32.1019 The same formula are given in the book Pendry J.B. "Low energy electron diffraction. The...

I solved it, but then saw another solution online and am wondering if is is correct (since it is much faster than mine) and if my reasoning of it is correct 1. Homework Statement Two loudspeakers emit sound waves along the x-axis. A listener in front of both speakers hears a maximum sound...

Why do radio waves pass through walls while visible light can't? I guess this has something to do wit the wavelength. What I know is that higher wavelength means higher ability of penetration. So why radio waves penetrate obstacles?

When looking at the FFT spectrum of a sonometer, I noticed that the harmonics decayed faster than the fundamental. Why is this?

i know it's an absurd question, but why are longitudinal waves called waves although they aren't wave-like?

I have some skepticism. All it says is "enhances molecular interaction", which sounds kind of vague to me. They also say it "shapes" the favor. None of which make sense. So either I don't understand how its possible (which is possible) or its some nonsense... which is also possible. Anyways, I...

If air is made up real little particles, then why would the waves made up of these particles not bounce off? Here's my attempt at an explanation for the principle of superposition for soundwaves. The wave is transferred by the air molecules hitting the ones adjacent to it. But because air is...

Hello I am having trouble understanding why the horizontal component Fx is equal to the F for a wave on a string I am trying to understand Energy in wave motion. The picture attached is a representation of my problem. My textbook tells me that this is because it is a transverse wave which means...

I have seen so many questions and confusion about the difference between angular velocity/speed and angular frequency. Usually, answers were always given in the context of uniform circular motion (angular speed) and simple harmonic oscillation (angular frequency), but this is what causes the...

Homework Statement A monochromatic plane wave with wavelength 500µm is propagating through a dissipative medium with refractive index 1-0.0002i. It approaching the edge of the medium, and will pass out into free space. If the angle of incidence is not 90°, how much will the wave deflect as it...

I have learned about the electric fields of static charges and those of moving charges. From what I gather(although I have not really learned the specifics) when charges are accelerated they emit electromagntic waves which are essentialy an electromagnetic field progagating through space. My...

h is plank constant and v is frequency. I was using this to derive the TDSE. But I ran into problem because to substitute k^2 in E=h^2/8mpi^2 * k^2, I can use single derivative of psi squared or double derivative, both of which tend to give the correct answer. So, is my assumption of energy...

I am looking at a couple of very interesting papers, published in MNRAS, that deduce, that the accelerated expansion of the Universe we observe can be attributed to gravitational waves, produced by a very distant merger of two or more universe-mass-scale black holes. The last one is on the...

I understand that a radio telescope can be tuned to receive radio waves generated by neutral hydrogen atoms present in galactic gas, for example, within the spirals of the milky way. I think I understand that the incoming radio waves will be a mixture of red- and blue-shifted photons depending...

Homework Statement A plane electromagnetic wave travels upward. At t = 0, x = 0, its electric field has the value E = 5 V/m and points eastward. What is the wave's magnetic field at t = 0, x = 0? Homework Equations B=B init. sin(kx-wt) E=E inti. sin(kx-wt) E=cB The Attempt at a Solution I am...

I am doubting that any plane wave is generated from a spherical wave. At large distance the radii of curvature becomes so large that we can think it as plane. Like we se Earth surface as plane though it is spherical. Is it true? I have a mathematical proof for my argument!

How does the sun emit or radiate its electromagnetic waves? https://imgur.com/odqclja Is it like the first picture where it might be spaces in between the waves or more like the picture under it where the waves are uni formally (I think is the right word) with no space in between them? Or...

So this isn't really homework help at all, I'm currently doing a biology undergrad, this is something I saw in high school, but I never really understood. Basically, I've been given the basic explanation of the Huygens principle, but it doesn't really make sense to me. It seems to me like this...

i have heard how our broadcasts will be seen by aliens far away or whatever. but i realize those signals are going to "attenuate" by d^-2 anyway... how come in astronomy we can see light sources millions of light years away? shouldn't those signals be far too weak to detect after such a long...

Hi to everybody ! I was thinking about something which confuses me about wave emission. The question is simply the following: Does an electron emit light when it accelerate? or just during its deceleration? or maybe when acceleration and deceleration alternates in some order? I'm not really...

I was searching for d Broglie's original Papper of matter waves, I didn't get any thing on internet, please anyone help on this?

I have recently started learning about waves. We didn't really formally describe what a wave is, but instead started by looking at a concrete example namely harmonic sinusoidal waves in 1d. We then introduced the wave equation in 1d and showed that the sinusoidal waves indeed satisfy this...

Homework Statement A mass m attached to a spring of spring constant k emits sound at frequency f, detected by a collinear observer at distance r. If the mass has maximum velocity v_0, what is the total number of waves the observer detects in one period of oscillation? Homework Equations...

So I thought I understood something well, and then I went to explain it to someone and it turns out I'm missing something, and I'd appreciate any insight you might have. If I think about Bloch's theorem, it states that ψk(r)=eik⋅ruk(r) where uk has the periodicity of the lattice. If u is...

Homework Statement Two slits (of width ##a=39 \mu m##) are lighted up with a monocromatic wave of ##\lambda=632,8 nm##. The distance between slits and the screen id ##D=4 m##. The distance between the slits id ##d=195 \mu m##. In front of the slits there are a convergent lens with focal length...

Newton's law of gravitation cannot be compatible with relativity because the gravity from a massive object applies a force to all other masses infinitely fast. General relativity is supposed to correct this flaw by setting a speed limit on how fast the effect of gravity can reach a distant...

I was doing a thought experiment last night. Gravitational waves, being like any other type of wave would cancel each other out and create a refraction pattern of strength. While we do not have definitive proof there is a black hole at the center of every Galaxy, we do know, through...

I would like to know how exactly or if the velocity of air molecules affect the light i.e electromagnetic waves passing through it. Ignoring the effect of pressure and/or temperature differences in the air which might also affect the light (due to changes in refractive index).

Do electromagnetic waves have potential and kinetic energy like springs, strings, etc. If so how are they calculated, inter-related? What is the total energy? Are the energies fluctuating over time? I am a physics hobbyist so generally the first answers should come with the least mathematics...

Are gravitons postulated to be excitations of gravitational waves? If so, and since gravitational waves have been unambiguously observed, then gravitons must exist, no? If not, then what is the postulated relationship between gravitational waves and gravitons? Are both deemed/postulated to...

Does the spark frequency = the interruptor frequency = radio signal frequency. From the sources I have found these frequencies don't seem to match. We use a 9V DC one at school. Many Thanks

it seems to me that during a high energy event that a space time compression wave would be created which would then normalize as it spread out. A particle on a back end wave would become close enough to the front end wave that it could tunnel between the two as "distance" is compressed. We...

Homework Statement Light of wavelenghs 4.80x10^2 nm and 632nm passes through two slits 0.52 mm apart. How far apart are the second-order fringes on a screen 1.6m away? λ₁ = 4.80x10^2 nm = 4.80x10^-7m λ₂ = 6.32x10^-7m d = 0.52mm = 5.2x10^-4m n = 2 L = 1.6 Homework Equations (Maxima/Bright)...

I have included a screenshot of a part of my textbook that is giving me a slight bit of confusion. It's talking about how to get the formula for adding sines and cosines. The part that I am confused about is the very first formula introduced in the screenshot. From what I understand, we are...

In the video: The professor mentions how the wavelength will be the same for a moving observer vs a moving observer for a classical wave like a sound wave. However, how does that explain doppler shift? Don't we observe the effect because a moving observer measures a different wavelength than a...

well since gravity waves are supposed to have mass, they are supposed to be effected by gravity itself, and :/ how are we supposed to detect gravitational waves emitted from a black hole when none can get out?

Radio waves pass through everywhere without interacting with each other and that enables us to hear different phone calls and radios without disturbance. However, we do hear some noise sometimes because different signals interfere with each other. How are both of the last two statements true (if...

Homework Statement A closed organ pipe of length 1.00m is filled with a gas and is found to give the same note as an open pipe of length 1.30m filled with air, when both are resonating at their fundamental mode of vibration a) draw diagrams to show the nature of the waves in each pipe and use...

In Total Internal Reflection, the beam can still lose some energy as it reflects off the boundary of the medium it is within. This isn't covered under the Fresnel equations. The energy loss is probably lost in the form of evanescent waves. I tried searching for the formulae describing the...

Hello everybody, I am new here :) what exactly is the energy of the wave? how to think about it generally, in electromagnetic waves and in relation to amplitude? I can think about the kinetic or potential energy that a particle can get from that kind of wave or the sum of all such energy in all...

A couple of idle musings but I hope interesting ones: 1. If a drop of water lands in a still pond, circular concentric waves spread out. Is it possible to reverse this process with a large circular wave generator such that the waves converge and meet in the middle, and a drop of liquid jumps...

Homework Statement A boy fishing on the jetty observes water waves coming in from the ocean. He sees 4 waves pass him by in 2 seconds, each with a wavelength of 0.5m The speed of the waves is? Homework Equations v=d/t The Attempt at a Solution 4 waves pass him in 2 seconds. 4waves x 0.5m...

Note: I'm sorry if I have to use the template, but I already have the solution, I just do not understand it and need help understanding it. 1. Question: A firework explodes at a 40 metre height and gives off a bang which measures at 100 dB at ground level. What is the power of the sound that...

I have a question regarding a theoretical analysis of Ultrasonic waves : The next picture represents a system of transducers sitting on fixed boards: Datum: * there are 4 transducers ( represented by blue color , indexed by letter ' T ' ) , each outputting Ultrasonic wave (represented by...

To whom it may concern, I am having issues with a given assignment in my quantum mechanics class. The instructions listed below are all I have to go on since the prof. is not available for discussion and I have searched through at least 15 articles regarding plane waves and a dozen textbooks...

Homework Statement The fundamental frequency of a violin string is 283 Hz. Calculate the frequency of the 2nd harmonic. Known: f = 283 Hz Homework Equations v = fλ f(n) = n*v/2L λ= L v(sound) = 343 m/s The Attempt at a Solution λ = 343/283 = 1.21 m f(2) = 2*343/2*1.21 = 283 Hz. I'm getting...

I am curious as to what the maximum amplitude of gravitational waves is. I have read that the maximum amplitude as such is equal to two but I cannot seem to find again a reference that states this clearly.

Homework Statement Hi, I'm stuck on some question.. There are given to waves in the following equation: The question asks to find the energy density of them, and after it to find the kinetic and the potential energy in t = 2.5 seconds. V = | 2 | [m/s] T = 4 [N] p (density) = 1 [KG/M]...

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...