Electromagnetic Definition and 1000 Threads

Is Magnetic field conservative or non-conservative in nature, I have searched online regarding this, it seems to be a divided house, MIT professor Walter Lewin demonstrated that it is non-conservative using an experiment, but still many arent convinced with the way experiment was conducted...

I was having a discussion with my friend the other day. He had just attended a lecture about Paul traps. He told me that the Paul trap potential has a stationary point in the middle, which is a saddle point, and that the 2 pairs of opposite poles are oscillating between being positive and...

Ive asked this question so many times on various forums and i feel there is a simple answer that i just haven't heard yet. I realize that an EM wave is represented as a sine wave, but from what i understand, that's not the physical motion the fields take. Let's say we take a snapshot at the peak...

I have seen the retarded potentials and what not, but what has always bothered me is why these field solutions reflect when they meet surfaces. I have looked and looked, but there seem to be no analytical explanations for this, only empirical ones. So my gripe is, since electromagnetic waves...

Let's say I have some source that generates a spherical wave that propagates outwards at the speed of light, and I have a vehicle that is charged. The wave will accelerate my vehicle periodically and eventually bring it to great speeds. Does this work?

Ok, so here is my question. Basically I believe that frequency and amplitude have no effect on each other. But in a black body, the intensity of the radiation is directly affected by the wavelength. With the intensity being the square of the amplitude, and wavelength being the inverse of the...

Homework Statement Show that the force on a moving charged particle F = qv × B from a magnetic field pointing perpendicular to the velocity produces a centripetal force and that this is equivalent to the equation pc = ABρ, where B is the magnetic field strength (in Tesla) and ρ is the radius of...

I was curious about electromagnetic waves and whether or not they can be canceled in the fashion I require. First I will state a few principles that I am considering in the paragraph below and the paragraph after will pose the question in full. A Wireless router produces a signal that...

Hello all, I have a question relating to charge. I understand that when a positive charge is near a negative charge it creates an attraction. This attraction is explained by the electromagnetic force and by the exchange of electrons. My question is this, how can a new particle such as a photon...

When Gamma Rays collide it is possible to form various units of matter (ie proton, electron, etc). Does anything happen when photons collide that are of other frequencies other then a ricochet? If X-Rays collide with other x-rays does anything happen? Also, if anything does happen, what would...

I mean, you can only start to see the effects of gravity when a large amount of matter is in one place. What if all the electric or magnetic fields in every single atom of that planet or star or black hole, ect... combine into one large field, big enough to create what we know as gravity?

Suppose a permanent bar-magnet is placed inside a toroid/torus and the toroid is then completed and power applied. How will the magnet move? Will it move?

I know they're represented as sine waves but what would they actually look like in space. they wouldn't actually physically go up and down and side to side like a sine wave would they? I have seen representations of sound waves, which i assume is a longitudinal wave, but not a EM wave.

Homework Statement An iron core with a solenoid coiled around it is in a circuit with a switch and a dc current supply. In front of it, there is a iron ring tied to the ceiling such that it faces the solenoid without touching the circuit. When the switch is turned on what is observed and...

All electromangtic radiation comes under one continuous spectrum. http://en.wikipedia.org/wiki/File:Electromagnetic-Spectrum.png Different wavelengths of this radiation has different properties which is very evident in real life. However the whole concept remains extremely mysterious to...

This isn't actually coursework, I'm doing some studying on my own. These are my very preliminary attempts to wrangle with tensor notation, so please be patient with me. I'm trying to get the components of the electromagnetic field tensor from \partial^{\mu}A^{\nu}-\partial^{\nu}A^{\mu} But...

in electromagnetics , considering boundary conditions of dielectric and perfect conductor , inside conductor E = 0. So, there should not be any time varying magnetic field. But in many books i have seen that inside conductor normal component of B is 0 because there is no time varying magnetic...

I'm trying to build a small electromagnet of a 5v breadboard i had set up, but I've run into some troubles. It doesn't work, and I'm trying to figure out if I just need to pump more current through it or if the core I'm using is made of the wrong materials. Does it have to be straight up iron...

I know that gamma rays are a part of the electromagnetic spectrum and that they are also a type of nuclear radiation, created upon the decaying of a large, unstable nucleus. Is there any difference between these 2 definitions of gamma radiation? Is gamma radiation only created in the way...

Hello, I have to give a presentation on an application of electromagnetic field theory of my choosing, and I was wondering if anyone had any suggestions that might be more interesting than the ones that have been suggested. It's for a 2nd year university level physics (E&M) course, so the...

Why does nickel reflect infrared, but gold does not? I've seen devices that shine infrared at a metal surface and measure the reflectance. They're mainly used for looking at thin film coatings. For example, you could have a metal part made of nickel, and thinly coated in gold. The gold...

1. In the theory of electromagnetism, we say light(and others with different λ) propagates through anything by the alternation of the electric and magnetic field... I am still reading things abt the theory,haven't finished yet... But some things seem not clear... It seems 'em' is saying the...

The electric field in a cubical cavity of side length L with perfectly conducting walls is E_x = E_1 cos(n_1 x \pi/L) sin(n_2 y \pi/L) sin(n_3 z \pi/L) sin(\omega t) E_y = E_2 sin(n_1 x \pi/L) cos(n_2 y \pi/L) sin(n_3 z \pi/L) sin(\omega t) E_z = E_3 sin(n_1 x \pi/L) sin(n_2 y \pi/L)...

Homework Statement http://imageshack.us/photo/my-images/194/55132039.png/ http://imageshack.us/photo/my-images/194/55132039.png/ How much curret flows trough circuit ABCD when the center of the circuit (O) is distance r from the straight wire? I think these are the relevant equations...

Hi! I'm currently reading 'An Introduction to the Philosophy of Physics, Marc Lange' where he is arguing about the reality of the electromagnetic field etc. While reading I caught myself in not having the concept of what that makes something real in place. How would one define something as a...

I know we can contain the energy/plasma from a fussion reaction with an electromagnetic field, but would an EMF protect from gamma rays? Would it be possible to deflect a nuclear blast with a powerful enough EMF?

I understand that the EM tensor is a way of expressing the electromagnetic field in a frame invariant way, but how is it derived? Please use the (-+++) convention as I mostly use that.

According to relativity, time rate differs in regions with different gravitational potentials, i.e. the closer we are to the source of gravitation the slower time passes. Does anyone know what happens to time in electromagnetic fields?

How to express electromagnetic field tensor in curvilinear coordinates, that is given a curvilinear coordinates (t,\alpha,\beta,\gamma) with metric tensor as follows: n_{\mu \nu }= \left[ \begin{array}{cccc}h_0^2& 0 & 0 & 0 \\ 0 & -h_1^2 & 0 & 0 \\ 0 & 0 & -h_2^2 & 0 \\ 0 & 0 & 0 & -h_3^2...

Hi , i am a high school student ( class 10 ) and after reading about electromagnetic induction iwas thinking about what if u place a wire coil connected to a circuit in the magnetic field / near a generator ? Because electricity is turned of for a fraction of a second there will be great...

Given the above quote reference Helium within our Heliosphere, I have a grouping of questions for the electromagnetic wise. If Earth and Jupiter were both placed within a dense Helium plasma region/field of our Heliosphere at the same time; and considering He plasma's high electrical...

Electromagnetic relay(check my solution please :) ) Homework Statement The following diagram shows an electric device that uses some of the principles discussed in this lesson. Discuss the sequence of events that occur when switch 1 is closed. *The diagram is in the attachment, you don't...

If the intensity of an electromagnetic wave is 80 MW/m^2, what is the amplitude of the magnetic field of this wave? (c = 3.0 x 10^8 m/s, permeability of free space ''miu subzero''= 4π × 10^-7 T ∙ m/A, permittivity of free space ''E subzero'' = 8.85 × 10^-12 C^2/N ∙ m^2) 80MW/m^2= 80,000,000...

Every book I ever read describes a electromagnetic wave as a phenomena generated by charged particles accelerating. This will produce a change in electric field that induces a magnetic field. But, due to Maxwell equations a change in magnetic field will also produce an electric field. So, if a...

Quite a vague question here, and I'm not entirely sure I'll be able to get a satisfying answer out of this one, but here goes. Fields such as the electric or magnetic field are introduced as vector fields that allow you to calculate a force at a certain point in space. In this interpretation...

Homework Statement Which of the following will produce Electromagnetic radiation? Explain Your answers. a) Alternating current in a TV transmitter b) The cord of a vacuum cleaner while it is being used c) The circuit of a battery operated CD player d) A positively charged particle...

This is just a conceptual question that I've been personally wondering about. So light has a magnetic field wave perpendicular to an electric field wave. I don't quite understand the magnetic field wave though. I thought that magnetic fields were not supposed to have a beginning or end. They...

Let's suppose that on Earth I have two devices which permits me to detect the gravitation produced and electromagnetic waves (photons) emitted by the Sun. Then, the Sun suddenly disappears. Which of the two devices will notice first that the Sun has gone, i.e. which wave propagates faster, the...

Homework Statement The figure below shows a plane electromagnetic sinusoidal wave propagating in the x direction. Suppose the wavelength is 56.0 m and the electric field vibrates in the xy plane with an amplitude of 20.0 V/m. (a) Calculate the frequency of the wave. (b) Calculate the magnetic...

Hello I am new to this forum and wanted to ask a question on em induction. I know if a current passes through a wire a magnetic field around the wire is produced and can be amplified by having a coil of wire. If that is then placed in a magnetic field (like between a north and south pole...

Apparently for emf to be induced in a coil, the magnetic field (or part of it) has to act along the normal to the coil face. So does this mean that the coil moves side-ways through the magnetic field? where instead of moving through its length (its longer side), it moves through the coil face...

I haven't been able to find any literature that answers this question in a pleasing way. Also, all sources on the internet are contradictory. If electromagnetic waves (out of phase since they are emitted by the gaseous atoms in discharge tube) sent through a diffraction gitter interfered with...

Homework Statement Two metal rods are placed on two parallel smooth conducting rails , under uniform B field lines . The metal rod on right-hand side is initially moving at a constant velocity of 3 m/s , while the other one is initially at rest . What would be the subsequent motions of the two...

Homework Statement Q1: explain how the setup shown in the diagram acts as a break? Q2: Electric and hybrid cars use regenerative breaking. At high speeds, the car can be slowed by reversing the direction of the electric motor so that it acts as a generator. Explain how this system...

Say I were to shine a laser in a particular direction and quickly turn it off. After a certain time, the radiation passes through a region of space. Some force field (e.g. electric or magnetic; assume gravity is negligibly small) is then turned on as the radiation passes, such that no mass or...

Imagine that an electron is traveling with velocity +v inside a uniform sphere of charge at potential +V. In the rest frame of the electron the charged sphere has velocity -v. Thus in the rest frame of the electron, inside the charged sphere, there is a vector potential A given by A = -...

A while back (thread) you guys helped me understand why \tilde{F}=m\frac{d\gamma\tilde{v}}{dt} (3-vectors) as it follows from \bar{F}=q\Psi\bar{v} (4-vectors) and \tilde{F}=q(\tilde{E}+\tilde{v}\times \tilde{B}) (3-vectors). However, I had the impression that one also uses...

As I understand it, there are these categories: radio microwave infrared light visible light ultraviolet light X-rays gamma rays It seems that microwaves are really just radio waves that happen to have a very short wavelength, with the distinction that radio & microwaves are waves...

i have gone through that photon is force carrier of em force..but in macroscopic level as far as I studied I know em force is designated with field in macroscopic rather than a particle like interaction.so how can they justify that em force is managed by photon.If photon is more plausible is it...

dear all, I have a question about Electromagnetic field tensor. As I was reading introduction to relativity by Hobson, I saw this sentence: "in order that the rest mass of a particle is not altered by the action of the erforce we require the latter to be a pure force, so: u.f=0 1) what does it...