Em wave Definition and 225 Threads

Howdy everyone. 1. Ok, so we have and electromagnetic wave propagating through a vacuum. We know wavelength, and the magnitudes of B in the x and y directions. Also, B=[Bx(i)+By(j)]cos(kz+ωt). That's all the prereq stuff. 2. So Intensity is: <P>/A & (1/2)Bmax^2/Zo I'm def feeling...

Hello Everyone, I am making an LRC circuit by having a Coil attached to a Capacitor attached to a Light-bulb which is attached to the Coil. Provided that the radio signal (of 2000 Mhz) I'm trying to "collect" is strong enough and the coil/capacitor is properly tuned I should see the...

I am using "Advanced Engineering Electromagnetics" 2nd edition by Balanis AND "Antenna Theory" 3rd edition also by Balanis. I found an inconsistency in how to characterize RHC (CW) and LHC ( CCW) elliptical polarization. 1) In Advanced EE Page 159, for \vec E(0,t)=Re[\hat x...

For RHC EM wave travel in +z direction, the unit vector is \hat {E}=\frac{\hat {x}+\hat{y}j}{\sqrt{2}} ignoring the ωt-kz. What if the RHC EM wave travels in -z direction? The unit vector should be \hat {E}=\frac{\hat {x}-\hat{y}j}{\sqrt{2}} ignoring the ωt+kz. Am I correct?

Homework Statement Hi everyone, As part of my final year project I am modelling the propagation of an electromagnetic wave through a medium of refractive index, n. I begin at the boundary between vacuum and the medium, x = 0 and propagate forward to some distance x. I have initially...

This is not a home work, it is part of the textbook on elliptical polarization. Attached is a page in Kraus Antenna book, I cannot verify the equation on the last line. Here is my work E_y=E_2(\sin{\omega} t \cos \delta \;+\; \cos \omega {t} \sin \delta) , \sin\omega {t} =\frac {E_x}{E_1}\;,\...

Attached are the drawings. Does the polarity Eof depend on \Gamma =\frac {\eta_2-\eta_1}{\eta_2+\eta_1} So if \eta_2<\eta_1, the Γ is negative and the polarity of the reflected wave is opposite polarity? I understand \theta_i=\theta_r and all that. As shown in the drawing, if you look at...

A metal box will block most EM waves. Is this because the oscillating E field will be canceled when in contact with the conductor. And because the oscillating E field is the source of the changing B field does this then kill the B field.

A "unit magnitude" EM Wave? Homework Statement Write down the solution of Maxwell's equations corresponding to a plane polarised EM wave of unit amplitude and wavelength λ=2∏m, polarised in the zy plane and traveling in vacuo in the minus y direction.Homework Equations ∇.E = 0 ∇.B = 0 ∇xE =...

Consider an infinite sheet of surface current described by the surface current density , K=dI/dl, where dl is a length element perpendicular to the current. For this sheet, the magnetic field B=μK/2, above and below the sheet, independent of the distance from the sheet, where μ is for free...

then how can you tune into, say, 101.1 when its not at 101.1 MHz all the time given the frequency change?

Let's say we have a radio wave coming into a receiver. When the phase is near 0, does this mean that fewer photons are being absorbed by the receiver compared to when the phase is near 90? (Hope I'm using the right terms here)

Hi eveyone, I am new to this forum and I hope that I can gain lots from this forum. Recently, one question comes into my mind, that is about the possibility of splitting the electric component and magnetic component of EM wave. This two components seem to always stick together. However, if...

In wikipedia's description of transmitter, if an alternating current is given to an antenna, then the antenna radiates off em wave. But why this happens so?

I have been reading different articles about EM wave modes, it is said that in TE waves the E_z is zero, similarly for TM H_z is zero, and TEM both E_z and H_z are zero. How about the E_x and E_y in TE wave? Someone said E_y is also zero and only E_x exists in TE...is this true? Is it...

Hello all! I am trying to understand ER on a more intuitive level. I can see the relationship between energy and frequency. The relationship between amplitude and photon number is less clear. So far I have E = hf. I understand that the intensity of light is a function of the number of...

I'm reading my course book on ELectromagnetism and it is talking about a wave moving in the y-z plane but with polarisation in the x-direction, and it says that the equation $$\mathbf{E}=E_0 2i sin(k_0 z\ cos \theta) exp[i(k_0 y\ sin \theta - \omega t)]\mathbf{e}_x$$ Shows that there is no...

Hey all. I don't really understand how the fields of an EM wave have a vector. I think I understand the vector of a static EM field, but I'm having trouble understanding it when it comes to an EM wave. Could someone help me out a bit? Thanks. (I'm sure it's something simple that I just don't...

Consider a lens of diameter d and a focal length f >> d. Let the cross-section area of the lens be S = N*λ^2. Let a plane wave be focused from S to an area S1=λ^2. Then, by the linear superposition principle the electric field intensity in the area S1 will be N times greater than it was in...

i was studying incidence of EM wave at a plane dielectric boundary and encountered equations in the attachment . I just want to know if n2 > n1 then electric field amplitude at the boundary increases . So from where does this extra value comes ? n1 and n2 are intrinsic impedances of 1st and...

Hello everyone! This is my first posting. According to Maxwell, an accelerating charge emits a EM wave. All the books I have referred to, talk about the frequency of oscillating charge. How can we determine the frequency of EM wave emitted by a charge that is accelerating linearly? Thank you...

Hi! Does electromagnetic waves induced emf or current in the coil or inductor due to faraday law as the magnetic field is continously changing in em wave?

According to this review: http://lanl.arxiv.org/pdf/quant-ph/0508202v1.pdf A classical EM plane wavefunction is a wavefunction(in Hilbert space) of a single photon with definite momentum(c.f section 1.4) , although a naive probabilistic interpretation is not applicable. However, what I've...

We all know that the wave vector of a propagating plane electromagnetic wave indicates the direction of propagation. What does it mean by the "in-plane" wave vector of that plane wave?

Hello, I have a loop antenna I have been messing around with for a few years and I understand most of the physics behind it, especially with regards to Faraday's Law of Induction; however, I'm trying to work backwards now to determine a source voltage at a distance. For example, if a...

Homework Statement The electric field of a spherical electromagnetic wave in vacuum can be written in the form of: E(r,θ,phi)= A(sin(θ)/r)*[cos(kr-ωt)-(1/kr)sin(kr-ωt)]phi Show that E is consistent with ALL of Maxwell's equations in vacuum and find the associated magnetic field...

In a single photon at a time double slit experiment. Is it the wave function or electromagnetic wave of a photon that is interfering? If both, what is the contribution of each? Remember that the electromagnetic wave is not the wave function of the photon. In a single photon, it has wave...

My bad for the spelling fail in the title. Homework Statement I am utterly confused with the mathematics in a section of my notes, I swear that it's wrong - and it related to a piece of homework which I cannot understand. The electric field vector in a z-directed monochromatic EM wave is...

How can I find the induced current density by EM wave in a material? Should I have ma = Fbinding + Fdriving + Fdamping like treating it as a spring? Then the current density should be charge density of the material x velocity (ρv), isn't it? Is there any condition the EM wave cannot...

Homework Statement A 50cm wavelength EM wave in air has 50mW/m^2 of energy. what is the frequency? what is the average E field? What is the B field strength? What would be the λ in water? Homework Equations I found the λ. How do I find it in water The Attempt at a Solution...

Alternating current produces EM Wave. What determines the frequency(or wave length) of an EM wave related to current or voltage?

Homework Statement Show that in vacuum the magnitude of the momentum density vector of a plane electromagnetic wave is equal to the energy density divided by the speed of light, c. Homework Equations \vec{S} = \vec{E}x\vec{H} The Attempt at a Solution This doesn't seem too hard if you know...

I was just reading about EM wave propagation and had two questions I would appreciate an answer to. 1-I read how the electric and magnetic fields of an EM wave oscillate sinusoidally and perpendicular to each other and the direction the wave is traveling. Is there any significance or special...

Homework Statement Given the following EM wave propagating in vacuum, find the direction along which the electric field oscillates and the direction of propagation of the wave: \vec{E} = (-3\hat{i} + 3\sqrt{3}\hat{j}) 10^4 e^{i[\frac{\pi}{3} (\sqrt{5}x + \sqrt{5/3} y10^7 - 8.1246 *10^{15} t]}...

why electromagnetic waves are represented by complex numbers?

Homework Statement Show that the electromagnetic wave equation \frac{\partial^{2}\phi}{\partial x^{2}} + \frac{\partial^{2}\phi}{\partial y^{2}} + \frac{\partial^{2}\phi}{\partial z^{2}} - \frac{1}{c^2}\frac{\partial^{2} \phi}{\partial t^2} is invariant under a Lorentz transformation...

is it possible to make am em wave of length 5(lamda)...lamda=wavelength of em wave...

Assume a infinite depth good conductor block with width in y and length in x direction. Boundary is at z=0 and air is at z=-ve and conductor at z=+ve. Let a voltage apply across the length of the block in x direction so a current density established in +ve x direction. We want to look at the EM...

My understanding from the book about EM wave that E and B is perpendicular to the direction of propagation only in medium that is charge free so \nabla \cdot \vec E = 0. What cases when E and B not perpendicular to the direction of propagation? Thanks Alan

OK, so recently I have learned that in the early 20th century, while Max Planck was attempting to explain the quantum nature of light, two men named Philip Lenard and Heinrich Hertz discovered the photoelectric effect. They found that an electron must absorb a specific amount of energy...

Homework Statement So I'm trying to show for a specific, given EM plane wave in vacuum that kx - \omega t = k' x' - \omega' t' but I'm running into some difficulties. I'm hoping someone can show me where I'm going wrong. Here's the setup: In the lab frame K, a plane EM wave traveling in...

My understanding is that the EM field at r.t generated by a radiating source can be described as the amplitude of the EM fields at r, at time t. Is there a corresponding photon associated with that wave? A unit surface area at large r from the source will have less energy passing through it...

hi, i have a problem understanding why the wave equations are as such if wave is moving left, it is f(z,t) = Acos(kz + wt - d) if wave moving right , f(z,t) = Acos(-kz -wt + d) finally i don't know what this represent f(z,t) = Acos(kz - wt + d) where A is constant , k is wave...

For an EM wave in vacuum, we know the energy density is given by1/2 e E^2 for the electric field, with a similar expression for the magnetic (e is permittivity of vacuum). E^2 implies that the energy oscillates as a cosine squares function if we represent the E field as E_0.cos [ kx -...

If you take a permanent magnet and wave it back and fourth, or even just move it along in one direction, this seems like it should create an electromagnetic wave. If so, how would one compute the frequency, and could you possibly detect it with a radio if you shielded it from other noise?

I keep looking at a sketch of the mutually perpendicular electric & magnetic fields in an EM wave. The sketch (and my text) says they are in phase, i.e. their maximum values occur simultaneously, ... ...but the discussion centers around the changing E field producing the B field and...

This is a theoretical question not a homework question, so if this is the wrong section to post this in please let me know. But my friend has this idea that if he sent an electromagnetic wave at a certain frequency at a surface it could create a current and this in turn could charge a battery...

I understand application of Snell's law for transition from one medium to another but I have a question regarding this model. When an electromagnetic wave transitions from air into a conductive medium does the wavelength change instantaneously as the theory seems to imply or is there a boundary...

why according to classical, electron circuling around the nucleus will emit EM wave and lose energy and collapse? I know electron undergoes circular acceleration, but why emit EM wave?

How did maxwell derive the momentum of electromagnetic wave to be E/c ?