Electromagnetic Definition and 1000 Threads

Homework Statement Using the transform of the electromagnetic tensor F between frames, F'=RFR^{T} verify that: i) the perpendicular component of the magnetic field in the frame, S', moving with velocity v with respect to the frame S, can be found from the transform of B_{\bot} in S...

Hello everybody! For a physics project, I'm trying to create an electromagnet exposed to varying current, determined by a sensor. This sensor will measure the distance between a magnet under the electromagnet and the electromagnet itself, and then we'll need to convert this distance to the...

The Dirac electron in the Higgs vacuum field v and an electromagnetic field with vector potential A_\mu is described by the following equation: i \gamma^\mu \partial_\mu \psi = g v \psi + e \gamma_\mu A^\mu \psi where g is the coupling constant to the Higgs field and e is the coupling...

Hello everyone, First to preface I am not a scientist and have the heart of one (I purchased the heart from eBay... jk). Anyway I have a lingering question regarding Europa: Ok, I get the science about the tidal forces on Europa that flexes the rocky portion of Europa heating up the...

Would electromagnetic coupling between an electron with charge e and an electromagnetic field with scalar potential V_em add to its mass in the same way as its coupling to the scalar Higgs field? i.e. mass_electron = g V_Higgs + e V_em Somewhere I got the picture that a left-handed...

Please teach me this: How can we unify electromagnetic and weak interactions?Is it correct that the SU(2) symmetry(flavor symmetry of fermions) is spontaniously broken(by Higgs Field) and the symmetry(be broken) ''become'' U(1)xSU(2) symmetry that is the symmetry of electroweak interaction...

Hi everyone I have a question that has been bothering me for a while now. I have basically built a Faraday cage using wire mesh. I know there is a relationship between the mesh hole size and the wave suppressing ability of the cage. As I understand it an electromagnetic wave can be thought of...

In the picture below http://www.geo.mtu.edu/rs/back/spectrum/e_mag.gif a bulb is placed on a wire parallel to the direction of the electric field. The bulb is directly on the x-axis where the two waves cross each other. 1. Would the bulb glow when the wire is parallel to the direction...

The general formula for the electromagnetic four-vector produced by a moving charge is the Lienard Wiechert formula, which involves the retarded position of the charge. However, in the special case where the motion of the charge is a uniform velocity motion, the result becomes extremely simple...

Homework Statement Hi In Griffiths it is stated that any possible wave can be written as a sum of plane waves f(z,t)=\int_{-\infty}^{\infty}{A(k)e^{i(kz-\omega t)}dk} This is a sum over spatial frequencies. In another book I have, they write the H-field as H(r, t) = \sum_n{C_n H_n(r)\exp...

You know how a microwave oven has a mesh on the door so visible light gets through but not the microwaves? Can such a thing be done with infrared radiation too? Is it possible to block heat from getting through a mesh but not visible light?

Homework Statement http://dc10.arabsh.com/i/03594/qn9gr42q192z.png What is the direction of current in ring 2 if : a) ring 2 moves towards ring 1 b) ring 2 moves away ring 1 The Attempt at a Solution I used Fleming right hand rule but I'm not sure if it is true, a) the...

Hi, I am looking for clamping circuit for electromagnetic waves. I have a wave which has amplitude of 5 and -10. is it possible to clamp it to 1 and 0 respectively. I want a positive side clamp to be +1 units and negative side clamp to be 0 units. is it possible to realize using any...

how can microwaves heat food?

What determines the wave length.

Both are energy right? I'm asking cause I'm trying to understand the double-slit experiment and I'm just wondering how they can be sure to treat the electron as a particle. Could it be performed with for instance whole atoms or maybe the cores or something else that's more obviously matter...

Hello, Recently I have learned that magnetism causes the Lorentz force. The electric force makes sense to me in terms of virtual photons. But how do virtual photons give rise to magnetism and the Lorentz force. Is it because when the charged particle moves through an magnetic field it comes...

I have skimmed relevant links in wikipedia, and some external links regarding electromagnetic fields, but would like a simple (I'm no physicist) answer to the following question that I have. When one, for example, takes two strong permanent magnets and aligns so that there is repulsive/or...

My first posting after joining today so starting off "light" - I know a terrible pun but please be kind as I will ask a lot of basic and seemingly dumb questions from my simple mind in my quest to learn a lot as quickly as I can! I will try to word this as best I can but, how exactly do EM...

Hello all! I am getting into the electromagnetic waves section in my optics class and in some of these derivations, they are using expressions that I cannot remember how they were derived or the context of them. My book from my E&M class I took awhile back is currently at my house and I am at...

Say one had three intense laser pulses and one weak reference pulse coming together on the surface of a thin nonlinear medium as if coming from the corners of a square. The three intense laser pulses mix, and there will be the third order mixing k1+k2-k3 or k1-k2+k3 or whatever coming out in the...

I'm having some trouble understanding visually the propagation of an electromagnetic wave. I'm self-studying electrodynamics so I've never had someone explain this properly to me. I understand an electromagnetic wave is a propagating disturbance in an electromagnetic field. Originally, I...

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.

Homework Statement If I take a magnet and drop it though coil then the graph would have an increasing voltage until a maximum and then a reducing emf (until 0) and then a further reducing emf until a minimum and then an increasing emf again graph looks like this...

[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...

13. A plane electromagnetic wave is traveling in the negative y direction. At t=0, the magnetic field at the origin has its maximum magnitude of 5.300×10-7 T and points in the positive x direction. Which axis does the electric field lie along? Answer with a single letter: x, y, or z. WARNING...

Hello, This is not homework, as I'm not in school :) I was wondering if there are any standard equations for electromagnetic waves interfering with each other. For instance, can I change the frequency of a wave by hitting it with another wave of a different frequency? I can find info on...

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...

Greetings all! I'm completely new to Quantum Mechanics (my PhD research is in Computer Vision) and I am planning to apply some concepts to my research. I would like to know whether it's possible to get the Wave Equation over the components of a \mathbf{B}=(B_\phi,B_r,B_z) field induced by...

Hey! I stumbled across this problem while reading Wald's "General Relativity", but it belongs to Electrodynamics. In problem 3 of chapter 6 one has to find the general form of a static, spherically symmetric Maxwell tensor, which is clearly F_{ab}=A(r)(dt)_a \wedge (dr)_b+B(r)r(d\theta)_a...

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...