Electromagnetic wave Definition and 196 Threads

Ok, I'll try to make my question as clear as possible, but since the question arises from confusion, it may be difficult. In an electromagnetic wave, what exactly is waving? If the answer is field strength, then why do things like the size of the holes on the screen on a microwave oven, or...

Homework Statement An 80 kg astronaut has gone outside his space capsule to do some repair work. Unfortunately, he forgot to lock his safety tether in place, and he has drifted 5.0 m away from the capsule. Fortunately, he has a 1000 W portable laser with fresh batteries that will operate it for...

Homework Statement a plane electromagnetic wave of intensity 6.00 W/m^2, moving in the x direction, strikes a small pocket mirror of area 40.0cm^2, held in the yz plane. (a) what momentum does the wave transfer to the mirror each second? (b) find the force that the wave exerted on the...

Can someone explain to me how an electron can re-radiate an electromagnetic wave in a certain direction after being under the effect of the incident electromagnectic wave?

Hello ! I have a very old doubt about Electromagnetic Waves, I hope somebody can help me. Is the electric field of an EM wave really an Electric Field? I mean, what is the difference between that E field and an Electric field produced by, for example, an electron? If we have an EM wave...

Homework Statement What is the y component of the magnetic field at point O at time 0.227*E-16 s? Given: Frequency: 2.20*E16 Hz Max value of B-field: 4.00*E-8T when t = 0 at point O Homework Equations I think the following two equations could potentially be applied to the problem: B =...

I know that a changing magnetic field creates a changing electric field, which creates a changing magnetic field, which in turn creates a changing electric field. My question is, if one were to shake a magnet really hard would this create an electromagnetic wave? Possibly a radio wave. I say a...

The following statement came out of Wikipedia "Maxwell's correction to Ampère's law was particularly important: In 1864 Maxwell derived the electromagnetic wave equation by linking the displacement current to the time-varying electric field that is associated with electromagnetic induction...

Hello everybody, First excuse me for my English. Could someone please explain how far the electromagnetic wave of a coil travels? Does it depend on the current flowing in the coil? The coil diameter? The coil's number of turns? What will happen to the waves if we increase the current of a...

Homework Statement Show that intensity of radiation(EM wave) falls off with depth z as I(z)= Ie^(-2niwz/c) where I = initial intensity and ni=complex paert of refractive index Homework Equations I have tried the solving the solution using poynting vector. I have been...

If the electromagnetic wave is descirbed as: E=Eocosw((eu)^1/2z-t)i + Eosinw((eu)^1/2z-t)j Find the corresponding magnetic field and the poynting vector.

What happens when an electromagnetic wave reflects of a surface at an 90 degree angle and continues moving along the same path as it came from? Will the two waves that are moving in opposite direction interfer with each other to from a standing wave pattern? This seems to be the case when...

Homework Statement A speeder is pulling directly away and increasing his distance from a police car that is moving at 29 m/s with respect to the ground. The radar gun in the police car emits an electromagnetic wave with a frequency of 8.0x109 Hz. The wave reflects from the speeder\'s car and...

In certain circumstances, when an electron collides with an anti-electron, the interaction produces two gamma photons. The reverse process would be a gamma photon colliding with a gamma photon, such that the interaction produces an electron and anti-electron. A gamma photon is a high...

How come the energy of an electromagnetic wave depends only on its frequency? Given by E = hf. How come the energy depends only on the frequency of the wave and not on the magnitude of the E component of the wave? Doesn't the energy depend on the amplitude? Or is there no such thing?

Hi all, I have some questions about photons. I'm at the end of the semester of PhysII in the quantum mechanics section and I'm trying to understand how photons determine the property of an electromagnetic wave. The way the textbook describes it the electromagnetic waves are made up of...

A simple question How can one talk of a Plane Electromagnetic wave, when it moves within 3 dimensions, i.e. E and B?

Electromagnetic wave? Hi. Wich experiments show that an electromagnetic wave is a wave? And what kind of wave? How i think of it? Sure not like a wave on the ocean, there is no ocean there. So? thanks

Hi I have a presentation tomorrow and have to explain a few wave equations. I am using a book to walk me through them but there is one point I don't understand: At one point the book states: Because k=(angular frequency)/c, we will represent the waves of the electric field as: e^i...

The problem states: Verify by substitution that the following equations are solutions to equations 34.8 and 34.9 respectively. E=E(max)cos[kx-wt] B=B(max)cos[kx-wt] Equations 34.8 and 34.9 are provided in the attachment along with the problem itself as stated in the textbook. I'm not...

Hi All, Em waves propagate in varying ground conditons, in the ground the velocity of em waves is reduced since it is dependant on the relative dielectric permittivity, the realtive magnetic permiability & electrical conductivity. This will more than likely make no sense at all? My...

I tried to see how we go about *creating* and electromagnetic wave. To do that, I take a charge 'Q' rotating in a circle of 'radius' r in the y-z plane, with it's center as the origin with an angular velocity \omega. The electric field at a point (x, y, z) is given by: E(x, y, z) = E_x(x, y...

Please consider a plane wave that propagates through a dielectric with friendly properties (isotropic, non-conducting...) with speed c/n. What would happen if we remove the dielectric and the wave continues to propagate in empty space?

Consider please a conducting wire located in a plane electromagnetic wave propagating in the positive direction of the OX axis The wire is normal normal to the direction of propagation. Have you seen an expression for the potential difference between the ends of the wire? Thanks in advance for...

Please consider the following problem: A plane electromagnetic wave propagates throug a stationary medium with phase velocity u<c. Consider an observer that moves with speed u relative to the medium. In J.P. McTevish, "Maxwell's equations in media and special relativity," Eur.J.Phys. 21...

First of all I have to say that translating specific words from native language to english, is not easy. So I hope that you realize what is going on: What did I do wrong ? (Traveling waves from: http://en.wikipedia.org/wiki/Waves ).

Electromagnetic Wave Prob. (Is this a typo/error??) http://img519.imageshack.us/img519/4536/errorko2.th.jpg This is the book's solution to an E&M problem. I typed in the part that is enclosed by a red box. Am I not correct, and the "official" solution is wrong?!? It's basically a...

Homework Statement A plane electromagnetic wave, which is polarized in the positive y-direction, propagates in the negative z-direction. What is the direction of the magnetic field of this wave? Homework Equations My choices are: +z direction. -y direction. -x direction. +y...

i desperately need the equation which relates the power of a an electromagnetic wave from a source which continously emits only one photon at a time.

Homework Statement Consider a medium where \vec{J_f} = 0 and {\rho_f}=0, but there is a polarization \vec{P}(\vec{r},t). This polarization is a given function, and not simply proportional to the electric field. Starting from Maxwell's macroscopic equations, show that the electric field in...

now if light is an electromagnetic wave then why don't we realize the electromagnetic energy on lighting up a bulb or do we feel it? if yes then in what form?

I have yet another problem that I need help with. An elctromagnetic wave with a frequency of 7.0 MHz forms a standing wave pattern on a transmission cable. The velocity of the wave in the cable is 0.95 of the speed of light in a vacuum. the length of the cable is such that the third harmonic...

What is the phase relationship between the magnetic component and the electric component of an electromagnetic field. Is it in phase, or 90 degrees out of phase. I see it both ways in a Google search ?

B = k / w ( Z x E) Check this equation by deriving the units for B w = omega Z = z hat

Do colors or pigments reflect or let through certian wavelengths of radio waves the same way the colors reflect or allow light to pass? If so does this apply for all electromagnetic waves?

I'm just a hobbyist in things quantum and in the course of my reading, I have found it a bit confusing figuring out which parts of quantum theory deal with finite numbers of discreet values and which parts require continuums. For example: Last night I was reading up on qbits and in the course...

In quantum physics light is considered both (or neither) a probability wave and a photon. But where does the eletromagnetic wave come into the scheme of things in quantum physics? Is the electomagnetic wave merely an approximation to many different types of discrete photons (ranked by their...

Can someone please explain what an electromagnetic wave would look like. I've heard it being decribed as a massless particle but i don't think that is an accurate description. I am asking about the proportions of the wave so that i can visualize it in my mind.

Hi there. We always put the time dependent part of the wave functions as e^(iwt). Of course there is a reason! but I don't know it. Can you help me? Thanks in advance. Somy :smile:

Hi everyone, Have anyone ever seen a paper on "Depolarization and Scattering of Electromagnetic Wave form Moving Surface with Roughness" or something relevant? I'll be thanks if give me a reference. Cheers

Hi, We were told to show that the magnetic flux density B obeys a homogenous wave equation. This case applies to electromagnetic waves in a homogenous, linear, uncharged conductor. Now I know that the wave equation for magnetic flux density is as follows. [ tex ] \nabla^2-\epsilon\mju \frac...

Electromagnetic wave; the classical model... There appears to me to be an obvious flaw in the classical version of electro magnetic waves (before we even consider quantum theory. :rolleyes: ) Forgive me if I'm wrong but surely fields cannot travel as waves - after all, a field permeates...

This one doesn't make sense to me. A lost person may signal by flashing a flashlight on and off using morse code. This is actually a modulated EM wave. Is it AM or FM? What is the frequencey of the carrier, approximately? How can a light wave be AM or FM? I don't get it. I thought...

An electromagnetic wave has a frequency of 25000Hz. In what part of the electromagnetic spectrum is it located? can someone please help~? What do I do~~~~ to get answer~~! ><

Dear reader, can any on explain me what is a electromagnetic wave? -benzun please go easy with me

I have simple question here that I've been wondering about for sometime now, and here it is. In classical physics when an charge is accelerated it creates an oscillating electric field which creates an oscillating magnetic field, a electromagnetic wave, and each field carries energy with it. So...