Electromagnetic Definition and 1000 Threads

we know light bends and loses energy when it travels in gravity..what abt influence on light when it travels in EM field..similarly can anyone trace out what happens in weak and strong force fields as welll.I guess its complex..

Hi fellow members! I have a serious confusion for light being an electromagnetic wave? since the we know that electromagnetic wave is produced due to the motion of charged particle.Light reaches us from the sun due to nuclear fusion reaction but light is produced due to the heat or energy...

Scientifically, it doesn't make sense why you can't just wind up wire without really much air in the middle. In order to get more wire closer to the magnetic flux, why wouldn't you just wind up the coil tighter? I keep seeing ferromagnetic or air cores. Why not a tightly would wire so more...

Hi everybody! Please explain to me how can we consider static electromagnetic field in point of view of Quantum Field Theory.Because varying electromagnetic field can quantize to photons,so we can consider varying electromagnetic field like a ''set'' of photons. Thanks very much in advance.

This isn't a homework problem - I can't understand a particular statement in my professor's notes. As such, I hope it's in the correct forum. Homework Statement The Hamiltonian for a charged particle in a potential field A is \hat{H} = (1/2m) ( -i \hbar \nabla - q A)^{2} The square...

How Eddy Currents Produce Attractive Electromagnetic Forces--Maglev Hello, I am working on a paper about maglev systems and am trying to describe attractive electromagnetic suspension systems, but I am having a little trouble exactly visualizing how this works, which from what I have read is...

I was just thinking about electromagnetic fields and magnetostatics. Magnetostatics is the study of magnetic fields where they do not change or very little. I was wondering if a static magnetic field is still considered part of a Electromagnetic field? Since the magnetic field is not changing...

I am having trouble understanding how a light wave travels through a medium, such as the Earth's atmosphere when emitted from a light bulb... I have read some topics on the difference between transverse and longitudinal waves, but I am having trouble understanding how they exist. I can imagine...

I have trouble understanding the concept of electromagnetic waves. my textbook has the following explanation for electromagnetic momentum. It's not very clear to me. [ light reflecting from a perfect reflector will leave the surface with its initial momentum, thus having twice its initial...

So what i understand from my professor about the electromagnetic waves is this : an electric charge has an electric field E a moving electric charge induces a magnetic field B The electromagnetic wave produced is due to the moving charge which has both components E and B... But my...

1. A closed loop is held stationary in the magnetic field between the north and south poles of two permanent magnets held fixed. Can we hope to generate current in the loop by using very strong magnets? well, my doubt is: as magnetic field is a vector and since we have two pairs [one...

What is electromagnetic duality for Maxwell's equations in free space without sources? Is this symmetry valid when there are conventional sources? If not, what hypothetical additional sources are needed to restore duality symmetry?

Hi There is lots of text, but it is actually just a presentation of facts and thoughts to explain where I am in all this. There are two main questions: 1) Are the incident waves from a very distant source, say a star very far away, interfering with one another to create one or more resulting...

I understand the relationship between velocity and wavelength when the refractive index changes but I can't fully understand why frequency cannot change. What would happen if it did? why can't the speed of light stay constant as frequency and wavelength change to keep it. Is it because of...

Electromagnetic fields mostly have a stress-energy tensor in which the trace is zero. Is traceless stress energy tensor always implies Ricci scalar is zero? If yes how to prove that?

Hello everyone, I have the following problem understanding electromagnetic induction. THis is not a homework question but it's a thought experiment I seem to not succeed in doing. Let's take the situation where you move a rectangle shaped plate with a speed perpendicular to a homogenous...

I took a physics competition recently and found I missed 6 questions on electromagnetic induction and the like. I've always been shaky here, so I'm wondering if anyone can give me an online resource, or just explain to me exactly how it works (i.e., Lenz's law, etc., etc.)? I'm sorry for not...

Hello everyone, How are you doing? I have a doubt about electromagnetic induction, in three particular cases. I need to confirm that I have the right concepts, so I ask for your help. The main problem: Imagine that you have a permanent magnet, axially polarized and rotating on its...

Is there any mathematical relation between the value of charge(ie proton/electron) and radiation which is being emitted? I m sure energy is conserved in this process so does that mean electron decelerates in process of radiation ?

Hi, I'm trying to work through something and it should be quite simple but somehow I've gotten a bit confused. I've worked through the Euler Lagrange equations for the lagrangian: \begin{align*} \mathcal{L}_{0} &= -\frac{1}{4}(\partial_{\mu}A_{\nu})(\partial^{\mu}A^{\nu}) \\ &=...

Dear all - I am new here so please be gentle :smile: I have searched the site for a few days but alas still have a few questions on something i am hoping to make...so with your kind help - here we go! I am looking to make a type of electromagnetic piston, basically i want to have an...

Hi, I'm wondering if there has been any actual experiments done to measure the speed at which magnetic fields propagate?

I recently read an article online stating that electromagnetic radiation is 'a form of energy emitted and absorbed by charged particles'. This isn't always correct, is it? I mean, I know that charged particles that are accelerating can emit bremsstrahlung and synchrotron radiation, but my own...

Homework Statement If I move a SQUARE conductive layer in a forward direction, with a magnetic field pointing vertically upward why is an EMF only induced in the left-right plane NOT the forward-backward plane??Homework Equations The Attempt at a Solution I would have thought that as BOTH...

Hello, why the electromagnetic waves move up and down instead of just travel straight? When an electron go in a lower energy level it relases a photon, but where does this photon came from? Thank you!

Homework Statement Hey guys, I am trying to draw out the electromagnetic absorpton vs frequency graph for a known dielectric constant ε in a medium but I am kind of stucked. I am studying from the Griffiths' book if you can catch me up from there, equations are on pg. 394, in chapter 9.4...

By Maxwell's equations, electromagnetic waves seem to come about by means of magnetic fields generating electric fields and in turn electric fields generating magnetic fields (the loop continues.) But how is this not perpetual in the context that energy is not conserved? It seems as if a...

Homework Statement You are holding a conducting loop of copper and looking at its circle. Behind it is a long current-carrying wire carrying the current from left to right. As you pull the loop toward you, what is the direction of current flow if any? A)No way to tell B)Counter-clockwise...

Homework Statement A quantum of electromagnetic radiation has an energy of 0.877 keV. What is its wavelength? The speed of light is 2.99792 × 10 8 m/s, and Planck’s constant is 6.62607 × 10−34J · s. Answer in units of nm Homework Equations E=hf v=fλ ... λ=v/(E/h) The Attempt...

Physics is not my forte, but I need some answers re EMFs. I want to buy a 30-ft sailboat that has an electric engine. (I have attached a link to the exact model for reference.) Further, my intent is to live aboard. I have been planning on making my permanent bed right over the top of the...

How much stronger is the strong nuclear force compared it to the electromagnetic force beyond what could be accounted for by the inverse of the distance squared?

Homework Statement A plane monochromatic electromagnetic wave with wavelength λ = 2.2 cm, propagates through a vacuum. Its magnetic field is described by \vec{B} = (Bx\vec{i} + By\vec{j})cos(kz+ωt) where Bx = 1.8E-6 T and By = 3.8E-6 T, and i-hat and j-hat are the unit vectors in the +x and...

In a nuclear reactor, what kind of energy is produced when the radioactive isotopes go through fission? How much of it is in the form of electromagnetic waves? Are the waves mostly in the UV and Gamma Ray region of the electromagnetic spectrum?

May I know that are there any different between the electromagnetic flux and magnetic flux? Are there any electromagnetic flux in a permanent magnet machine? What kind of flux will go through the permanent magnet machine's stator cores with copper wires on it? I am really sorry to ask so many...

Homework Statement Use the integral form and symmetry arguments to compute the electric field produced by the following charge densities: (i) Point charge q, placed at the origin, in 3 dimensions; (ii) Point charge q, placed at the origin, in 2 dimensions; (iii) Point charge q, placed at the...

In order to determine the temperature that an electromagnet reached after a 3 minute period the electromagnet was placed in a constant volume of water. After 3 minutes the change in temperature of the water was measured and from this using the equation Q=mcΔT the energy in joules transferred was...

hello world. it is know that electrostatic (coulomb's law) and magnetostatic (biot-savart law) fields lose their strength like 1/r^2. why do they say that electromagnetic field falls like 1/r ? is that true ? if yes how, can you explain please ? after all energy radiated from a point source must...

I hope this is the right forum for a first year undergraduate problem! The problem I've been working on is here: http://i.imgur.com/IhTtL.png I think that I have the correct answers, but I'm not sure. I think that the energy densities of the E and B field components will be (0.5)(ε0)(E^2)...

When a conducting wire is subjected to a changing magnetic field, what causes the electrons in this wire to move? Conversely, why does the movement of current in the wire (with a non-'moving' magnetic field) cause the wire to move? I understand these phenomena macroscopically (and that they...

Is it possible for EM radiation to exist outside the EM spectrum? I'm aware of the different frequencies at which energy can be radiated eg. radio, infrared, and gamma. But is it possible for objects to absorb or release energy at subradio or supergamma frequencies? Or is there a physical law...

Hi i was wondering what's is the difference between electromagnetic waves and fields or is a field just a number of electromagnetic waves. also i was wondering is it possbile to have an electromagnetic wave where there is only a magnetic field and no electric field and vice versa Thanks

Homework Statement A solid sphere of radius a rotates with angular velocity ω\hat{z} relative to an inertial frame K in which the sphere's center is at rest. In a frame K' located at the surface of the sphere, there is no electric field, and the magnetic field is a dipole field with M=M\hat{z}...

The covariant form of the Lorentz force can be written as m \ddot x^\mu =q F^{\mu \nu} \dot x_\nu and such a relation should prove by the quotient rule that F is indeed a tensor. But what kind of tensor is it? One can show that it transforms from an unprimed to a primed system like F'^{\mu...

I can find the metric tensor in cylindrical coordinates to be [1,-1,-1/r^2,-1] but how about the electromagnetic field tensor and thus the energy stress tensor? Is it just change the Ex,Ey,Ez to Eρ,Eθ,Ez? Is FσρFσρ still equal to 2(B^2-E^2)

1. How do we observe what goes through in a slit in the double slit experiment? If this is accomplished with EM that goes across the slit, then why does the electron not completely change its direction before it hits the wall. It still always hit the wall where you expect it to, even though the...

I apologize in advance if some of my answers don't quite make sense. I'm generally articulate, but not when it comes to physics I'm barely grasping. I did a lab and part of it was dropping a magnet through a coil, which produced a Voltage vs Time graph using LabPro. For trial 1 we had the N...

Hey guys, back again for some help if that's okay! I've derived a formula for an electromagnetic wave entering a material, as \underline{E}e^{-\frac{x}{\delta}}e^{i(\frac{x}{\delta}- \omega t)} x=direction of propagation t=time \delta=skin depth As you can see this describes the wave...

Homework Statement A flat coil of wire has an area of 0.010 m2and contains 100 turns. Initially the coil is oriented so that the normal to its surface is parallel to a downward constant magnetic field of 0.2 T. The coil is then rotated clockwise through an angle of 30oin a time of 0.10 s...

Hi I'm working on a science experiment and I need two electromagnets to push away from each other, but the two small electromagnets I've made (using two bolts wrapped in magnet wire and a D battery) just attract each other no matter which ends I put together. Am I doing something wrong? Do I...

Homework Statement An electric generator consists of n = 500 turns of wire formed into a rectangular loop with a length of 5 cm and width of 3 cm placed in a uniform magnetic field of 2.50 T. What is the maximum value of the emf produced when the loop is spun at f = 100 rpm about an axis...