Electromagnetic Definition and 1000 Threads

Hello all, I have a problem with a typical style of problem I seem to always struggle with. Just to clear this up, I am studying for my comprehensive exams later this summer. So I am going through past problems to bone up on the last two years of grad school. At which point I came across this...

Theoretically speaking, does the frequency of em wave range from 0 to infinity?

Let say a nanoparticle (graphene) is electromagnetic shield. If we send a pulse of magnetic wave will it get reflected back. If it reflects can that be interpreted. And what happens if there going to be infinite EM shielded nanoparticles. Is that any kind signal which will reflects back from...

As I understand it, the classical source-free electric, ##\mathbf{E}## and magnetic, ##\mathbf{B}## wave equations are solved by solutions for the electric and magnetic fields of the following form: $$\mathbf{E}=\mathbf{E}_{0}e^{i (\mathbf{k}\cdot\mathbf{x}-\omega t)}$$...

Homework Statement http://imgur.com/a/7CUcU What happens when you close W? What happens when you open W again at Q? If there is a ring of metal at Q, on the coil. Homework Equations There is no relevant equations in this case. The Attempt at a Solution North will be on top and south on the...

As the title suggests, I'm looking for a way to explain/describe the EM field to high school seniors. Mechanical transverse waves are easy. But since EM waves travel in a vacuum and require no medium it's hard to form a picture in the mind of the students. What is actually moving?

What I know: A ripple/wave in a field gives rise to a particle. For example, a ripple in electric field creates a photon. Question: Is this the same principle as probability wave which when observed reveals a particle?

Hello. I was playing with functions one aftenoon until I got this one: f(x) = sin(tan(log(x))). I was just wondering whether that function (at least, until the part that it doesn't get too compressed) has the same shape (to say it somehow) as the Electromagnetic spectrum...

I have a question about electromagnetic radiation, I drew this to better explain what I am trying to understand hopefully it makes some sense but what I was wondering is this... if you take two prism and let the light of the sun enter the prisms like in the picture I drew will they both have...

would be really grateful if someone could help throw some light on this - its probably really simple but I am typing myself up in loops! I have a piece of wire which is placed in an external AC magnetic field which is varying sinusoidally. The wire is folded to make two rings of radii r1 and r2...

Howdy all, I'm looking at having two (preferably) stainless steel rods inside a plastic tube (for insulation and so they don't touch) with a push spring inside and between the two rods pushing each other away from one another, when not activated inside of an electromagnetic coil. When the coil...

Homework Statement We have a coil with cross-sectional area of 2.4m^2. Magnetic flux density is of 0.29T Number of turns are 1. Initially the coil is parallel to magnetic field lines. (Coil's normal vector is perpendicular to field vector) Calculate the change in magnetic flux when coil is...

I am University Student currently working on a project to make a stationary hover board. This is just a prototype and does not need to support a human and only needs to support about 1kg but with as much "lift" or distance between the magnets as possible - (100mm?) Ideally we want to be able to...

Hi, My name is Kendall. After seeing the Back to the Future again, I have been once again fascinated by the hoverboards, as I'm sure many others are also guilty of. A couple hours of research into magnetism later, and I'm still stuck. I have little to no experience with magnetism, but I figure...

So I know that EM waves travel perpendicular to the electric and magnetic fields which are also perpendicular to each other. What I'm having difficulty understanding is since light is an EM wave and can travel through the vacuum of space, does that imply that everywhere in the universe there is...

Homework Statement Show that integrated track length in EM-shower is proportional to ##E_0##. Homework Equations ##E(t)=\frac{E_0}{2^t}##, with radiation length, ##x_0##. Knowledge that shower terminates at ##E_c##. The Attempt at a Solution The total track length is naturally the total...

Homework Statement The energy of a daughter particle in electromagnetic shower is approximated by, ##E(t)=\frac{E_0}{2^t}##. Show that the energy falls off like approximately ##E^{-2}##, for small ##E##. Homework Equations Nothing really. Just a matter of knowing how to differentiate. The...

Hi everyone, initially I would like to put into words that this equation in my attachment is provided by Julius Adams Stratton but he do not derive the equation. The only part I do not understand and can not derive is the "RED" part. He just says it results from light pressure. So, I would like...

We took electromagnetic waves this week, and They specified that only accelerated charges make electromagnetic waves. So from my previous reading on the internet about speed of causality, I came up with this. That if a charge is moving at a constant velocity, It's field follow is it...

Hello Is we apply a voltage at the ends of a coil, a magnetic field will be generated? Is that correct? Will that empty the battery that is responsible for the voltage or a partial energy from the battery will be stored in the magnetic field of the coil and after that the battery will not...

Our Professor said there will be still an electric field in empty space even without charges.Hows that possible.Space-time has a some quantum property that acts like this ?

Hi, So I can get the idea that the ac current in a radio transmitter produces radio waves of the same frequency of the ac supply, just like shaking a slinky sprung up and down but how does this translate into the radio waves as actually coming out as photons and for that matter other than...

What composes the E Field of the Electromagnetic Wave where "disturbances" for propagation occurs? If electromagnetic waves cause disturbances in the Electric Field… what “is” in this E Field which photons Interact with? I ask because in Vacuum, there are no electrons to excite. So what is...

Homework Statement My book says that the electric field produced by changing magnetic flux is nonconservative in nature but it doesn't give any explanation. Homework EquationsThe Attempt at a Solution

Homework Statement A ring of mass m, radius R having charge q uniformly distributed over it and free to rotate about its own axis is placed in a region having a magnetic field B parallel to its axis. If the magnetic field is suddenly switched off, the angular velocity acquired by the ring...

Homework Statement .[/B] On the course, I was asked a question: What is less absorbing electromagnetic wave: metal or glass? Explain why. The Attempt at a Solution Now, I'm not sure if i did it correctly. I answered that glass is less absorbing electromagnetic wave due to it's structure and...

Using the Lagrangian : L = ½mv^2 - qφ + qAv What is the physical intuition of Av ? I know that A is the magnetic vector potential and that v is the velocity of the charged particle. I just don't know what their dot product means physically .

" We can put the Lorentz force law into this form by being clever. First, we write $$\frac{dA_j}{dt}=\frac{d}{dt}(\frac{\partial{}}{\partial{v_j}}(v.A)),$$ since the partial derivative will pick out only the jth component of the dot product. Now, since the scalar potential is independent of the...

Hi all, I'm studying electroweak spontaneous symmetry breaking at that time, see for instance Chang and Li's book ch 11. Have anyone an idea that if the charge operator is defined by: ## Q = \int (- e^\dagger e + \frac{2}{3} u^\dagger u - \frac{1}{3} d^\dagger d ) d^3 x ,## and the isospin...

I am developing a setup to generate dnamic eletromagnetic fields (EMF) which will be used to study the effect of EMF on bone francture healing in small animals.The setup has two solenoid coils which are separated by a distance and connected in series. Both coils are excited by 15 V AC that...

For a point in space if we have the values of E and H fields at a certain instant of time, we can tell the direction of the propagation of these values, which is the direction of the cross product vector E x H. Is this phenomenon time asymmetric or not ?

I know there have been discussions on electromagnets, but I think my question here is specific and hopefully quite different. Using DC power only, what amount of pull might I expect from, let's say, 48v of decent lead acid battery or batteries? It occurs to me that one could use an ebike...

Homework Statement...

Homework Statement Many sources of electromagnetic waves (stars and light bulbs, for example) radiate in all directions. A simple example of the electric field for a monochromatic electromagnetic wave produced by a spherical source is $$E(r,\theta,\phi,t)=A\frac{\sin \theta}{r} \big(\cos...

Homework Statement A long (infinite) wire (cylindrical conductor of radius R, whose axis coincides with the z axis carries a uniformly distributed current I in the +z direction. A cylindrical hole is drilled out of the conductor, parallel to the z axis, (see figure above for geometry). The...

since graphite conducts. if spiral shape is drawn with pencil on the wall (thick , dark lines) will a voltage difference appear between inner and outer end of the spiral when a varying magnetic field is switched on, normal to wall

Is there a meaningful way to convert the energy of an electromagnetic wave to a temperature? I mean this more along the lines of how the universe has a temperature of 2.7 kelvin due to electromagnetic radiation. I'm honestly just curious to determine the temperature of the universe after nearly...

Homework Statement A calorimeter is made from layers of lead (1.75mm thick) alternated with layers of scintillator. The radiation length ##X_0## of lead is ##0.64cm##. In an EM shower the number of particles doubles and the energy of each particle halves per radiation length travelled. The...

Homework Statement When a particle is accelerated toward another particle it is giving off electromagnetic radiation in the form of gamma waves. After a particle is annihilated, pions are transferred between the particles which turn into gamma waves which decay into (for example) an electron...

Homework Statement Homework EquationsThe Attempt at a Solution So I was given the electromagnetic E field equation in phasor form and I converted it to sinusoidal form. Is it correct ? Also will it be a reflected wave since we have (wt+Bz) and not (wt-Bz) ? Also will it be circularly...

Homework Statement A circular loop of wire is placed next to a long straight wire. The current I in the long straight wire is increasing. What direction is the current that's induced in the circular loop? Homework Equations The Attempt at a Solution I'm aware that the answer is clockwise...

Can anyone help me find any mistake in this expansion ? (I've asked it also in other places but I got no answer)) Pα= e Fαβ Uβ c = speed of light m = "rest" mass e = charge a = sqr(1 - v2/c2) v2 = vx2 + vy2 + vz2 dτ = dt a (proper time) momentum 4 vector : Pα = [mc/a , mvx/a , mvy/a ...

The electromagnetic action can be written in the language of differential forms as ##\displaystyle{S=-\frac{1}{4}\int F\wedge \star F.}## The electromagnetic action can also be written in the language of vector calculus as $$S = \int \frac{1}{2}(E^{2}+B^{2})$$ How can you show the...

Hi, I don't really get what the point of volume forces is, if electromagnetism is a volume force. Its obviously no surface force, but in my opinion the definition says that its no volume force as well. The link below describes volume forces as "a force acting on all particles (volume elements)...

Hello, I'm interested in building a small non-invasive battery powered device that wraps around a pressured 1/2" pipe for measuring potable water. From https://en.wikipedia.org/wiki/Magnetic_flow_meter and watching youtube videos, it seems they all use electrodes which contact the liquid...

Do falling charged particles radiate? Also, if I hold a charge still and bring a large mass close to it first on one side then another so that the particle sees a sinosoidally oscilating gravitational field will it radiate?

Hi, just trying to better understand this concept of electromagnetic radiation. My understanding thus far is that it is a traveling disturbance in the electric field. This picture here seems to help me see what is happening...

Homework Statement A farmer installs a private hydroelectric generator to provide power for equipment rated at 120 kW 240 V AC. The generator is connected to the equipment by two conductors which have a total resistance of 0.20 Ω. The system is shown schematically in Fig. 1. (a) The...

Homework Statement What are the electric and magnetic fields due to a charge that is moving with uniform acceleration? (Non relativistic) Homework Equations Retarded solutions for the vector and scalar potentials. The Attempt at a Solution My attempt might be an overkill because I'm using the...

The momentum canonical to the electromagnetic vector field A is straightforward to compute, as is explained in textbooks or webfiles (for example Bjorken-Drell or http://www.physics.buffalo.edu/gonsalves/aqm/lectures/10/lec-10.pdf ). Its time component is zero, while the spatial components are...