Electromagnetic Definition and 1000 Threads

OK, I need some help understanding some stuff. The way I see it: you've got 4 fundamental forces in physics right? I believe these are gravity, electromagnetic, strong interaction and weak interaction. The electromagnetic spectrum is basically waves with photons (photons in all of the...

How can I compute the intensity of an electromagnetic radiation if I know ##e_x, e_y, e_z, h_x, h_y,## and ##h_z##, where ##e_i## is the electric field component at ##i## and ##h_i## is the magnetic field component, also at ##i##? Thank you in advance.

I'm not sure where to ask this question or if it even makes sense... Say an electromagnetic wave passes through a point in space. The point experiences some fluctuation of electric and magnetic fields. But what happens after the wave has passed? Are there any lingering effects, like a "wake"...

Hello! I would like to ask about any software package, where interaction between a moving particle and a monolayer can be simulated. What i need to get is a spectral angular density distribution in the far-field zone within optical frequency range for a problem when a particle crosses a...

I just found this forum and would love some help on creating an indicator that lights up when placed next to a pulsed electromagnetic field. I'm thinking a small LED that lights up when placed near a pulsed electromagnetic field to confirm the electromagnetic field is active. How would I...

I've heard that em wave consists of mutually perpendicular electric & magnetic oscillations. Imagine that I've a unit charge at any point in space. Associated with this charge, there exists an electric field which diminishes with distance from the charge. If we set forth an oscillation in this...

I need help explaining that this assumption is not correct or correct: A product uses Radio waves to turn on a LED. Radio waves can be a form of electromagnetic fields therefore, a Hall Effect sensor could be used in this device to turn on that LED.

The book is expensive, so I want a book like Bekefi's and Barrett's Electromagnetic Vibrations,Waves,Radiation. Preferably at a higher level than this book. Thank you!

Hello everyone, For the past 4 years I have been working on a new type of musical instrument that fuses together elements from electronic music into the acoustic realm. The instrument consists of 26 strings inside a wooden enclosure that are actuated (or "bowed") by the use of electromagnets...

I was recently taught in school about the propagation of light as a combination of changing electric and magnetic fields. I had read somewhere that a magnetic field was basically an electric field in a moving frame of reference. So,I wanted to know if in some frame the propagation of light could...

Consider the arrangements shown in figure in which the north pole of a magnet is moved away from a thick conducting loop containing capacitor. Then excess positive charge will arrive on : (Plate B = answer) Am i correct in marking the side facing the magnet as south pole? ( because of Lenz...

Thanks for reading this As protons go faster and fast in the LHC they have a greater angular momentum (that's not at all the right term) to go around in circles faster and faster as they reach near the speed of light that greater inward attraction towards the magnet to rotate around in the LHC...

Hi folks, This is such a simple idea that I know I can't be the first to think of it so there has to be a "gotcha". Maybe an induced electric field working in the opposite sense? Is there a kind soul out there who can spare a few moments to educate me after reading what follows? Thanks About...

The electromagnetic force F = I*L*B * SinΘ will increase based on the value on SinΘ.What's the physical explanation for this? Why does the angle between vectors B and IL matter?

Electromagnetic field has a density of energy U = ε/2*E2+ μ/2* H2 And a density of momentum, given by the Poynting vector S = E x H For an element of volume dV you have a four vector of energy and momentum which is [E,P] = dV * [U, S] Being E the energy in the element of volume and P the...

Magnetic fields are less harmful than electric field and also a lot safer than being exposed to electromagnetic radiation. If data transfer is possible through magnetic flux then cancers and all those kind of diseases can be avoided. So, the question again is can a magnetic flux(movement of...

Homework Statement In a book I find the following derivation: \int (J \cdot \nabla ) \frac{\bf{r} - \bf{r}'}{|\bf{r} - \bf{r}'|^3} d^3\mathbf{r'}= -\sum_{i=1}^3 \int J_i \frac{\partial}{\partial r_i'} \frac{\bf{r} - \bf{r}'}{|\bf{r} - \bf{r}'|^3} d^3\mathbf{r'} \\ = -\sum_{i=1}^3 \int J_i...

I am just scraping the surface of electromagnetic induction, and I have some questions. First, let me illustrate what I know. I know that in a simple circuit with a battery and a switch, when the switch is turned on, a current flows which produces a magnetic field of strength in proportion to...

Can someone correct my understanding on electromagnetic waves please; I've clearly got the wrong end of a stick somewhere, but can't figure out where my misunderstanding is! Thanks. If I draw a classic EM wave with the electric field on the up and down axis and the magnetic field at right...

Hi, I would like to make a homemade electromagnetic device. It would be a 5cm diameter metal cylinder inside of a metal pipe. I would use electromagnetism to lift the (heavy) steel cylinder up the pipe, and then release it. It's meant to be used as a sledge hammer. Can I just wind a wire...

Are there any research or paper regarding electromagnetic effect on gases. For example does H2 gas physically move under electromagnetic field?

hello guys! I am confused about determining the equation for the induced emf in a rectangular coil with n turns rotating in a uniform magnetic field. According to faraday's law of EMI the emf induced in a coil of wire is the rate of change of flux passing through it $E_{induced}...

From introductory courses on EM, I was given 'sketchy' proofs that, in a EM field in vacuum, magnetic energy density is B² and electric energy density is E² (bar annoying multiplication factors; they just get under my skin, I'll skip them all in the following). Other facts of life: -FμνFμν, the...

hello is there a software that simulates electromagnetic field around atoms, materials? to simulate the forces that drive chemical reactions? thanks!

In the attached figure, light is incident at angle $${\theta}_{1} = 40.1^{\circ}$$ on a boundary between two transparent materials. Some of the light travels down through the next three layers of transparent materials, while some of it reflects upward and then escapes into the air. If $${n}_{1}...

From a conceptual point of view, how is it that Quantum Electrodynamics explains the interaction between two charged particles, (let's say two electrons)? I've heard people say that the electrons exchange photons, but how is it that an electron would know when to send off a photon and that it...

Homework Statement A monochromatic, electromagnetic plane wave is traveling in a non-conducting, transparent medium. Its real electric field is described by: ##E=100 \ cos (7.62 \times 10^6 (x+y+z) \ - \ 2.98 \times 10^{15} t) \ \frac{1}{\sqrt{5}} (\hat{y} + 2 \hat{z}) \ V/m## (a) What would...

Hi, trying to http://physics.stackexchange.com/questions/189766/teslas-egg-of-columbus# Tesla's egg of Columbus for a science project (). I have managed to cast a small rod of solid aluminium into a solid egg shaped piece of aluminium. I also have a large glass bowl that could sit inside an...

If you hit a bound electron with a photon corresponding to that electron's ionization energy, you ionize the electron. What if you hit the electron with a photon with less energy? Will the photon still add its energy to the electron? Will the electron re-emit the photon with less energy? Do you...

The General Relativity text I am using gives two forms of the Electromagnetic Energy Momentum Tensor: {\rm{ }}\mu _0 S_{ij} = F_{ik} F_{jk} - \frac{1}{4}\delta _{ij} F_{kl} F_{kl} \\ {\rm{ }}\mu _0 S_j^i = F^{ik} F_{jk} - \frac{1}{4}\delta _{ij} F^{kl} F_{kl} \\ I don't see how these...

Electrons pile up inside a metal up to a maximum value in k-space (meaning the have velocity) and occupying all levels at 0K, solving the Schroedinger equation as running waves. So electrons moving => radiation being emitted. But electrons can't move to a lower energy state, so that would mean...

hello! it is known that static electrical field can change the direction of movement of water dripping, etc I suppose this can also happen with other molecules that are dipoles or somehow influenced by electrical or magnetic field my question is what are the equation(s) that describe this...

I have a question about complex reflection and transmission coefficients. For example, I am modeling a wave in air (medium 1) ## \varepsilon = \varepsilon_0 ## reflecting on, and transmitted to, a medium 2 with ## \varepsilon = \varepsilon' -j \varepsilon'' ## If the wave would have traveled...

I have coils to transmit and receive the power supplied.When we supply the transmitter , it omit the electromagnetic wave.Does it omit one electromagnetic wave or a lot of them? If there are several of them, is the energy supplied ,divided equally to the number of waves or every wave carries the...

Is there a theoretical way to force electromagnetic waves transfere energy point to point like electricity instead omni-dirrectionally? I think it might be helpful for looseles wireless energy transfere.

hello, how to derive the hamiltonian for a free electron in electromagnetic field mathematically ? for a first step what is the lagrangian for a free electron in the EM field in classical mechanics ? the physics textbook always like to give the results directly.

Protons are in very close proximity with each other in a nucleus. This means there is constant electromagnetic interaction, of which the exchange particle is a photon. What determines the wavelength of this exchange photon? How do they exist in the nucleus: constantly being emitted, or staying...

Are the angular frequency in electromagnetic waves and frequency of a photon characterise the same physical quantity? I know that these come under two different theory, but I want to know whether these names (angular frequency of em wave and frequency of photon) mean the same physical quantity...

how can the electromagnetic waves be transverse and at the same time the E.M propagates in space (the definition of the transverse wave is that it is a wave in which it's medium particles propagate perpendicular to the direction of wave propagation) what i don't understand is that how can it...

For a photopolymer, the heuristic goes that longer wavelengths of UV light penetrate deeper than shorter wavelengths of UV light. For example, the UVA spectrum penetrates more deeply into the photopolymer than the UVC spectrum. What is the best way for this to be explained?

Homework Statement A rectangular loop of wire is placed next to a straight wire, as shown above. There is a current I in both the straight wire and the loop. The dimensions shown in the figure are a, b = 2.2a, and c = 8a. What is the magnitude of the force on the loop? Express your answer in...

Homework Statement A small circular metal ring of radius r is concentric with a large circular metal ring of radius 10r. Current in the outer ring flows counterclockwise due to an unpictured power supply. By adjusting the power supply, you can adjust I, the current in the large ring. The graph...

I am an 8th grade science teacher who has regularly used the pre-Bohr planetary-like model of the atom (like most 8th grade science teachers and textbooks) to help students start to understand atomic physics. But in my free time, I have repeatedly tried, and failed, to really understand the...

Hi I have a project to were I would like to melt ice from several feet away. Is there an electromagnetic transducer that I can operate to melt ice? What resonate frequency would I need to use? Any ideas? Thanks

Homework Statement If the magnetic field of a light wave oscillates parallel to a y axis and is given by ##B_y = B_m\ sin(kz- \omega t)##, (a) in what direction does the wave travel and (b) parallel to which axis does the associated electric field oscillate? Homework Equations The Attempt...

I seem to have a fundamental misunderstanding of the principle here. in the previous part it was required to sketch the graph for the hall probe. I knew since the speed was constant the field was cut at a constant rate hence a straight line was needed. However I did not understand why it...

Quick question about electromagnetic waves traveling through what's basically a capacitor. In the picture I have labelled areas that I'm curious about. 1. Is there a potential induced at A? 2. If yes, is it localized? I suspect the potential would be different at A and B. 3. Is it correct to...

Homework Statement Consider the charging capacitor in problem 7.34 (A fat wire, radius a, carries a constant current I, uniformly distributed over its cross section. A narrow gap of wire, of width w, w<<a, forms a parallel-plate capacitor) a) Find the electric and magnetic fields in the gap, as...

Homework Statement A plane harmonic electromagnetic wave of amplitude Eo and frequency wo is traveling in the positive x direction in a vacuum. It is linearly polarized with its plane of vibration at 45 degrees to the xy plane and the electric field is zero when x=0 and t=0 a) Make a sketch...

Say for you had a wire in a complete circuit inside a magnetic field (pointing inwards) perpendicular to the wire. You move the wire across (to the right) , cutting lines of flux, this induces a current in the wire. The induced current acts upwards using the dynamo rule (thumb is motion...