Electromagnetic Definition and 1000 Threads

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...

Figure below shows a load made up of a 50 W resistance, a 15 nH inductance and a 22 pF capacitance connected in series. The load is terminated to a two-wire transmission line with characteristics impedance of 50 W. (i) Determine the load reflection coefficient at an operating frequency...

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...

My teacher told us energy at a point of a progressive wave is proportional to square of amplitude, it is true for both mechanical and electromagnetic wave. But in the other lesson, he also tols us the energy of the EM wave is equal to hv, where h = Planck constant, v = frequency of the wave...

All electromagnetic waves carry energy. We kno that most of the electromagnetic radiation escapes the boundary of the "physical(corporeal) Universe". Therefore, much of the energy is radiating out to the voids spreading beyond material universe. Thus, a great amount of energy is lost...

In the double slit experiment, a wave is forced to go through a tiny slit. I do not understand what is stopping it from going through the barrier. After all, we can think of an electromagnetic wave as just the electric/magnetic fields of a sinusoidally oscillating particle, evaluated using...

Homework Statement Design and Perform calculation for an Electromagnetic Brake system of a truck having 3 Axils assuming that each axil carries equal load. The truck is carrying a load of 30000 Kg and the weight of truck is 6000 Kg and moving with 100km/h speed before the brake is applied...

Homework Statement When a third charge is placed at the origin, it is found that the force on it is zero. Find alpha? Two charges Q and 5Q are located as shown in the figure below. https://chip.physics.purdue.edu/protected/GiordanoEMimg/chapter17/17prob16.jpg If possible, please...

Hello friend. I am working of design of Electromagnetic Disc Brake system. I have performed some calculation. which you can find on following links. https://rapidshare.com/files/3568781938/untitled_folder.zip https://rapidshare.com/files/2134776724/untitled_folder_2.zip Please have a...

Hello, I have been playing around, making my own electromagnets. As I am out of my depth, I am experimenting with 1.5 to 9 Volt battery packs. I am hoping to have a setup where two electromagnets, around the size of a AA battery placed about an inch apart can noticibly repell each other a...

Hi, First post on these forums, but I've lurked a bit in the past. I'm doing a project on the Faraday Cage, and I have a quick question... I was wondering why a Faraday Cage can block electromagnetic radiation like a radio wave (which, as far as I can tell, is a "mix" of a magnetic field...

I will appreciate any contribtion to the question below. > You have a system that consists of a coil and magnet. The magnet, which is resting on a spring, is free to move up and down in the coil. This system can be modeled as a simple mass-spring-damper system with a...

Dear friends, I have a 5 minute presentation to give on the dependence of electromagnetic mass on its velocity for my physics class. This could be a very broad question to answer, but all I ask is to direct me to some useful links. I have troubles with that because I keep finding regular...

Hmm, not sure if this is the right place to be asking this. I am wanting to understand what effects electromagnetic energy can have when injected into the combustion process of hydrogen and oxygen? Can anyone tell me or point me what effects can occur or point me in the right direction to...

Hi all I am wondering as this diagram shows. Which way is the electromagnetic field(s) moving? http://www.biophotonicsresearchinstitute.com/Picture1.png Thanks.

hi, i have to build an dc electromagnetic buzzer for school project, but I'm having tons of trouble! can anyone offer advice to help me out? (like good websites with instructions or pointers?) i have most trouble with the connect/disconnect part of the buzzer! i have this nail that is fixed in...

I am currently reading and trying to solve most of the problems in Carroll's Geometry and Spacetime. I am generally okay at the math (I've done some mathy Riemannian Geometry type stuff), but am not overly good at some of the higher-level physics. Homework Statement (Chapter 1, Question 13)...

I have recently found a circuit schematic that can pick up radio signals without the need of a battery. Is this an example of electromagnetic induction? If so, how much voltage/current is induced? Does it change the properties of the electromagnetic wave, e.g. energy, wavelength, etc...

I'm having hard time understanding how exactly current that passes through inductor transforms energy into magnetic field and then into voltage, with 90° phase shift. I drew schemes representing sinusoidal imput current, its magnetic field and voltage relation. Is it correct? Would...

According to EM theory,in the absence of any interaction with matter, destructive interference in one location will always be balanced by constructive interference in another location keeping the law of conservation which means that there is no local conservation law for energy flux regarding...

Homework Statement The positron and the electron each have a rest mass of 9.11 x 10-31 kg. In a certain experiment, an electron and a positron collide and vanish, leaving only electromagnetic radiation after the interaction. Each particle is moving at a speed of 0.20c relative to the laboratory...

What is the mechanism for explaining the different effect of repulsion and also attraction due to the exchange of virtual photons in the electromagnetic forces? For example, the electrostatic force between two point charges, for both when they are oppositely charged and like charged?

Homework Statement The average intensity of sunlight at the top of the Earth's atmosphere is about 1400 W/m^2. What is the maximum energy that a 20 m × 30 m solar panel could collect in one hour in this sunlight? Homework Equations Not sure what equation to use The Attempt...