Electromagnetic Definition and 1000 Threads

I am having a problem understanding a thing in a electrodynamics problem. Imagine we have a wall at x=0 made of a perfect conducting material. Imagine now we have an electromagnetic wave traveling perpendicular to the wall with the electric field polarized in the y direction and the magnetic...

Homework Statement When we place a magnet in a long coil of wire the emf will be maximum when the magnet is at either end. What would happen when the magnet lies in the middle of the coil (i.e: the same amount of flux is interacting with the coil at all times). Would we have an induced EMF...

Are the amplitudes of the electric and magnetic components of an electromagnetic wave proportional? Or is the amplitude of the electric portion unrelated to that of the magnetic portion?

Homework Statement Electromagnetic waves contain time varying electric and magnetic field perpendicular to each other and also to path of progression. The phase difference between electric field vector and magnetic field vector is zero Homework Equations The Attempt at a Solution...

Homework Statement Electromagnetic Railgun consists of two parallel, distant from the horizontal, very long rails, after which moves perpendicular to the rails, linking them to the metal bar of mass m. The rails are in a vertical magnetic field intensity B. What is the speed limit the...

Can someone please tell me why the magnetic field makes the electrons flow round the coil in a generator? Does the force of the magnetic field have to go in the same direction as the coil?

A standing wave can be produced in a guitar string where the wavelength of the wave is the same length as the string (I believe this is referred to as the first harmonic) and where the string is an exact multiple of the wavelength of the wave (referred to as the second and subsequent harmonics)...

Homework Statement So here is the Problem : I am Modelling an interesting problem for a project i am busy with. I need to find out the force exerted on a single busbar in a 3 phase system, with each phase carrying 3300A. This is mainly so that i can deduce what size of busbar supports i...

Instead of quantizing the vector potential A^μ why we do not directly quantize the B and E fields in electrodynamics.

Hi. What physical meaning does scalar made from inner product of electromagnetic four potential, gαβAαAβ, have? Regards.

[Solved] Find electric and magnetic field amplitudes in an electromagnetic wave Homework Statement Find the electric and magnetic field amplitudes in an electromagnetic wave that has an average energy density of 1 J/m^3 Homework Equations u = Energy density u = (1/2)(e0)(E^2) +...

The electrical circuits in a house run on alternating current. This is a current of electrical charges that oscillates back and forth at a frequency of 60 Hz. Do these currents produce magnetic fields? Explain. Do these circuits radiate electromagnetic waves? Why or why not? I don't have any...

I have been wondering why photons can't go through matter and electromagnetic fields mostly unaffected while neutrinos can. Neither of them have an electric charge as a particle, and the basic description I see about neutrinos is always that "they are unaffected because they have zero electric...

A classical electromagnetic field requires you to know how far away from the source of the field you are, if this requirement is carried over to QED, how is the EM field of a particle known when we only know the probability of this particle being in a certain place?

I know that light is a form of electromagnetic radiation but I know that all electromagnetic radiation is not light. I know that light has four basic properties: 1) Light travels in straight lines. 2)Light can reflect. 3)Light...

Hello, why an electromagnetic signal propagate as wave? Wouldn't be more normal that electron travel in a beeline? Thank you.

From EM, the energy of electromagnetic wave in unit volume is \varepsilon_0 E^2. Does that mean the number of photon is \varepsilon_0 E^2/\hbar\omega ( \omega is frequency of wave)? In 1-D, E=E_0cos(\omega t+kx), then the number of photon in average is \frac{1}{(2\pi/\omega)}\int_{0}^{2\pi...

Suppose a spaceship is at 1 light year distance by Earth and it sends a message back home through an electromagnetic wave, we choose a frequency so that the wave will be a radio wave which requires little energy to produce. How do i know if the wave will reach the Earth? and what characteristics...

Looking at this in a weapon point of view, what would be the more effective one? Say we have a 155mm projectile traveling and hitting a hard target(metallic), lightly and heavily armored, at different times, both with an impact energy of 530 MJ. Also say we have a very short IR laser pulse...

From: http://answers.yahoo.com/question/index?qid=20090223155307AAgqbWk Question: Why are electromagnetic waves transverse waves? Answer: "Because they are generated by the rapid vibration of elecrons, which go side to side, perpendicular to the direction the waves travel (very very rapid...

Anything that occupies space creates a 'distortion' to a certain degree in the space time fabric and hence will experience gravitational force.And we know radiation does experience gravitation , this would directly imply that it occupies 'space' or 'volume' . The question now is .. how much volume ?

Electromagnetic waves consist of electric and magnetic fields having the same phase how?

point charges in an electric field Homework Statement Problem: A +8.75 micro C point charge is glued to a frictionless table. It is tied to -6.5 micro C point charge by a 2.5 cm string (weightless and nonconducting). A uniform electric field of magnitude 1.85*10^8 N/C is directed parallel to...

Hey everyone, Im doing this research and reading this http://science.hq.nasa.gov/kids/imagers/ems/gamma.html" it had a diagram of the depth of penetration of different wavelengths into the eaths atmosphere... my question is, How come x-rays penetrate deeper than visible light - what is the...

Homework Statement see attachment/picture im having problems with fields inside matter. i get the left side of gaussian surfaces/ampere loops. but for example this first equation's right side i can't understand. The Attempt at a Solution i would think the right side should be I since...

consider first , an induction motor... a rotating magnetic field is applied to an electrically conductive rotor, and the eddy currents induced will oppose the change in magnetic field experienced by the rotor, hence the rotor gets torque in an induction motor the rotating magnetic field is...

Homework Statement B field = xt in z direction in Cartesian Coordinate, t is time. Homework Equations obtaining the remaining field expression together with charge densty "rho" and conduction current J, so that all Maxwell's equations are satisfied. There is no unique solution. The...

Hi, I suppose I'm a little late to start here, but I just got hung up on the following: The field quanta in E&M is the photon and it comes from the gauge potential in QED A(x) A(x)=\int \frac{d^3 p}{(2\pi)^3 \sqrt{2\omega_p}}\sum_{\lambda=1,2}\left[...

Hi Guys, I have a doubt. When we think of a modulated wave, consider frequency modulation for example, does the wave contain photos of gradually changing energy (or frequency)?

If EM waves are pumped into a resonant cavity at it's resonant frequency will each incoming wave add it's energy to amplify the wave(s) in the cavity? I know that if you pulse a light source into a circular wave guide and you pulse the light source each time the light wave returns to it's...

Sorry for a naive question. In EM textbook and QM path integral textbook, the action and Lagrangian in electromagnetic interaction are S = L dt = e(\phi – A v) dt ---equ.(1) But in QFT textbook, the action and Lagrangian density are S = L d^4x = A J d^4x ---equ.(2) As I...

If you have a 3 phase 4 wire distribution where the 3 phase conductors and 1 neutral is inside a pvc conduit, how would you model the force of the electromagnetic field at a certain distance away from the conduit? Assuming the loads are balanced, the currents would sum to zero on the...

Homework Statement 1.Calculate the work done by the force F=i cos(pix/4) + j y2 along the path y=x2 in the x-y plane from (0,0) to (2,4). 2.Is the force F conservative? Explain. Homework Equations Work = Integration between a and b of F.dl The Attempt at a Solution 1. I know...

Hello every one . We know Radio waves carrying data When a radio device receives radio waves , It render the waves and we hear sound . Now my questions are : 1 - How data on electromagnetic waves are transmitted ? When a electromagnetic wave hit a atom it absorbed by the atom like this...

Homework Statement Electric and magnetic fields in many materials can be analyzed using the same relationships as for fields in vacuum, only substituting relative values of the permittivity and the permeability, ε = κε0 and μ = κmμ0, for their vacuum values, where κ is the dielectric...

Homework Statement Hi, here is the problem I'm having trouble with: The rms value of the magnitude of the magnetic field in an electromagnetic wave is Brms = 0.137 T. The intensity of this wave is approximately... Homework Equations E = cB I = (ErmsBrms) / \mu0 The Attempt at a...

Homework Statement I am high school student and was wondering how does electromagnetic field become existing? I konw equations describing are equations of max, but i do not understand how does field exist? equations of max describe but not tell why? that is my questions. Homework...

is it possible for electromagnetic field to exist without matter?

I would appreciate some help regarding the movement of an electron in a plane-wave linearly polarized electromagnetic field. Its simple enough question, but I am not sure what approach to take. Let's say the electron is at rest in our frame of reference and the plane wave is continuous...

Hello, Why does electromagnetic wave intensity attenuate exponentially with depth from its incident intensity in an object? Why is the relationship exponential? I just need a nudge in the right direction or more if you are willing. Thank you for any help!

why electromagnetic wave is transverse?

Could someone point me in the right direction on how low frequency (< 3 Hz) electromagnetic radiation is detected? I tried googling it, but my searches didn't really work; perhaps I was using the wrong terms? Another thing: what is the lowest frequency that has been detected, and what limits...

Hey guys, Im trying to design a electric gear shiftier for a motor bike. Basically I require about 200N of force to change gear with a 10mm throw (in both directions). I would like to use a tube neodymium magnet. (23mm diameter 25mm high with a 5mm hole throw the centre with a N48 grade) What I...

Hey guys, Im trying to design a electric gear shiftier for a motor bike. Basically I require about 200N of force to change gear with a 10mm throw (in both directions). I would like to use a tube neodymium magnet. (23mm diameter 25mm high with a 5mm hole throw the centre with a N48 grade) What...

Electromagnetic waves, aka light and such. What is it?. I know that it is a wave of energy, magnetic and electric forces traveling in wave forms but when struck turning into a particle. But what exactly are they made of? Is it just a pure wave of energy and nothing else to it? Do physicists...

I'm trying to design a pickup/reluctor that produces a specific waveform. I'm using an automotive ignition pickup and expermenting with different shapes of reluctor but the results I'm getting aren't making any sense. The pickup/reluctor are of the familiar design with a pickup coil wound...

Fig.35 shows a light and flexible conducting loop X freely hung on a smooth horizontal rail. A bar magnet PQ approaches the loop from the right. Which one of the following descriptions about this process is correct? A If P is a N-pole, the loop will be repelled to the left and its area...

Homework Statement An electromagnetic wave from a wire antenna travels (from the reader) toward the plane of the paper. At time t = 0.0 s it strikes the paper at normal incidence. At point O and t = 0.0 s, the magnetic field vector has its maximum value, 5.01E-8 T, pointing in the negative...

This is my first posting with the forum and I hope I have chosen the appropriate topic. I am a 25 year automotive technician and have been pursuing an alternative application for the automotive industry. It is the electromagnetic pulse engine, which basically utilizes a regular 4 cylinder...

Hi guys, I am too old to remember basic knowledge about electromagnetic waves :D I am looking for a combination of an electromagnetic wave and a material such that the wave can pass through human tissues, but it is blocked by the material. All I know is that X-ray/gamma can penetrate human...