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24 views

Shape of wavefronts for transverse modes in electromagnetic waveguide

I've been able to confuse myself about the shape (i.e. surface ripple/bend/tilt) of wavefronts for transverse modes in an electromagnetic waveguide, like a rectangular cross section waveguide with ...
3
votes
1answer
142 views

Do accelerated moving electrons radiate electromagnetic energy?

Do accelerated moving electrons radiate electromagnetic energy? Generally speaking, the charge should absorb energy instead of radiating energy in the acceleration stage, and release energy in the ...
0
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3answers
38 views

Would fast oscillating charged object emit light?

If I were able to mechanically oscillate an electrically charged object at frequencies of 430-580 THz, would the object emit light?
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0answers
13 views

How to incorporate refractive index in transfer matrix method

I need to determine the TE and TM reflections at the interface between a uniaxial crystal and air, using a matrix-based method, such as the TMM. I can do so using the Fresnel equation with ease, but ...
0
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1answer
23 views

Poynting vector flux on a closed surface

What does the flux of the Poynting vector through a closed surface represent? I know that the flux of the Poynting vector on a certain surface represents the power flowing through it. But if the ...
3
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0answers
17 views

Poynting vector flux in a tube (geometrical optics)

Let's consider the following tube (defined as the solid described by two arbitrary surfaces dA1 and dA2, and by all the rays which connect their boundaries): I read in a textbook that, because of ...
0
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1answer
20 views

Electric field from the intersection of two spheres with different charges

This question is repeated a lot, but I for two spheres with different charge densities, sphere one with radius a centered at the origin and charge density $\rho_1$, and sphere two with radius centered ...
2
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1answer
58 views

How can changing magnetic field produce instantaneously the electric field and vice versa? [duplicate]

Maxwell's curl equation for electric field says that time varying magnetic field produces electric field instantaneously but nothing can happen instantaneously according to special relativity. What is ...
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0answers
15 views

Guided propagation in transmission lines

Can you help me on understanding why we may say this transmission line the propagation is guided and there is not any radiation? It is a 2-conductors transmission line, in which the conductors are ...
0
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1answer
43 views

Can I think Transverse Modes in optical waveguides as an contructive interference phenomenon?

I am studying about Transverse Modes formations in optical waveguides. Q1. I got an impressions that this is a constuctive interference phenomenon. while waves that have phase difference 2pi*m; for ...
2
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1answer
63 views

Skin Effect Explanation

I do not understand some things about the Skin Effect. Its Wikipedia definition is: Skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor ...
1
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1answer
33 views

Help me distinguish between an Amperian loop and a surface

This image is from the Resnick-Halliday-Krane textbook. These images have been used to see that a correction was needed in Ampere's circuital law. What I am confused about is, how are the two end ...
0
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1answer
36 views

Biot - Savart Law and time - variable current [duplicate]

Is the Biot Savart law valid also with currents which are functions of time (for instance a sine wave)?
0
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1answer
31 views

Helmholtz equation and sources

it is known that starting from the Maxwell equations it is possible to get the following Helmholtz equations: In time domain it corresponds to a sinusoidal EM field, according to the wave equation: ...
0
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0answers
13 views

Most general case for Optical Fibers eigenvalue equation

In the system of equations leading to the eigenvalue equation for Optical Fibers, books always avoid the $\phi$ dependence, as mentioned in this previous question. This, however, implies some ...
-1
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1answer
107 views

Does a vibrating neutral object emit EM radiation caused by the vibration?

Does a vibrating neutral object emit EM radiation caused by the vibration? If the object is a molecule, does it radiate? and if the object is a atom? I am not refering to thermal radiation. It does ...
0
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0answers
12 views

A parallel between eddy current and Beer-Lambert law

For AC current flowing in wire eddy currents are the reason for current density decay as we move towards the center. Similarly, in Beer-Lambert law, for electromagnetic plane wave impinging on ...
2
votes
1answer
93 views

How do I transform flux density into temperature?

I have flux density data from Planck mission (in Jy) - measure in a certain frequency - and I would like to transform it to temperature data (Kelvin). I'm not sure if I should use Stefan Boltzmann's ...
1
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0answers
84 views

Why is the stress-energy tensor for electromagnetic radiation traceless?

A photon gas obeys the equation of state $\rho=P/3$ and hence $T^{\mu}_{\quad\mu}=3P-\rho=0$. (Can also be seen by expressing the stress energy tensor in terms of of the electromagnetic tensor as ...
3
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3answers
73 views

How is light as electromagnetic waves produced?

One of the upvoted answers to Why don't electromagnetic waves require a medium? says that the electromagnetic field is the medium for electromagnetic waves. It went on to say that if the ...
1
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0answers
13 views

Plasmon modes of cylinder metalic particle

Solving Laplace equation gives plasmon modes of spherical metalic particle radius $R$, plasma frequency $\omega_p$. Famous result is $l = 0, 1, 2, ...$ $$\omega_l = \sqrt{\frac{l}{2l+1}} \omega_p$$ ...
0
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0answers
38 views

EM-wave interaction with particles

I'm interested in EM waves acting on particles, but have a poor understanding since I haven't yet read a proper EM book and currently am doing more mathematical stuff. I've looked through a couple of ...
1
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1answer
132 views

What is the frequency distribution of the electromagnetic wave emitted by a charge accelerating along a given trajectory?

Charged particles radiate when accelerated.From a few other answers from Physics Stack exchange like What is the frequency of a photon emitted by an accelerated charged particle? and How ...
0
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2answers
35 views

Changing Refractive Index

Is it possible that the refractive index of a material could change?if so,what are those factors and what kind of variation could they bring?
0
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2answers
131 views

Does light carry heat both are same thing or different? [duplicate]

In many books it is written that light is an electromagnetic wave, as we know there does not exist any oscillator that can oscillate an electron with a frequency of light. My question is, how can we ...
-1
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1answer
51 views

Why is light moving transversal?

This question will be in some way complicated for different reasons - I am no physicist, I know about things like wave-particle duality, that the tranversal wave motion comes from change in electric ...
1
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0answers
32 views

Proof of differential and integral identities used in electromagnetics radiation

I am starting my studies in antenna theory and need help to prove the following identities: I) $\nabla^{'}\left[\mathbf{J}(\mathbf{r^{'}})e^{j\mathbf{k}\cdot\mathbf{r^{'}}}\right] = j\mathbf{k}\cdot\...
0
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0answers
50 views

Interpretation of the In and Out Field in the solution of ${\partial_\nu\partial^{\nu} A_\mu=4\pi j_\mu}$

In the solution of the wave equation for particles charged in motion given by ${\partial_\nu\partial^{\nu} A_\mu=4\pi j_\mu}$ , we have a homogeneous solution given by $\partial_\nu\partial^{\nu} A_\...
0
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2answers
32 views

Optical fibers eigenvalue equation considering $\phi$ dependency

Consider the system of equations formulated in a previous question (optical fibers continuity of tangent field components across the core-cladding interface): $$ \left\{ \begin{array}{c} e_z^{(1)}(r,\...
0
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1answer
52 views

Does a spinning electron stop spinning

An electron caused to spin in a magnetic field gives off synchrotronic radiation (Synchrotron radiation (also known as magnetobremsstrahlung radiation) is the electromagnetic radiation emitted when ...
0
votes
1answer
34 views

Basic question on Poynting flux and antennae

I am looking at a question (though my queries here are more regarding th underlying conepcts, which I don't quite understand) about a radio antenna that is polarising a conducting sphere. For ...
3
votes
4answers
72 views

Why does frequency remain unchanged in light refraction but wavelength doesn't? [duplicate]

Since the frequency of an electromagnetic wave does not change during refraction but the velocity changes, the wavelength must therefore change. But why doesn't the frequency change in the first place?...
1
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0answers
56 views

How can I get the wave number and wave vector? [closed]

$$\overrightarrow{E} = (-10 \hat x + 4 \hat z) e^{-j(2x+5z)}$$ I recently started to study electromagnetics, but I'm having a hard time following up. May I ask how to calculate the wave vector $\...
0
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2answers
39 views

What is the relation between the frequency of the light produced and the acceleration of the charged particle

We know that accelerating charges produce EM radiation. Can we derive a relation between frequency of the light produced and the accelaration of the charge ?
1
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1answer
63 views

Confusion about derivation of Abraham-Lorentz force

An accelerating charged particle produces EM radiation, so we conclude that there must be a reaction force acting on the particle, leading to the Abraham-Lorentz force: $$ {\bf F}_{rad}=\frac{q^2}{6\...
0
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2answers
42 views

What is the force corresponding to Lamor's formula for EM radiated power?

The rate at which electromagnetic energy is radiated is given by Lamor's formula. What is the corresponding rate at which momentum is radiated and hence force to this?
1
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2answers
83 views

How did Maxwell figure out the speed of light?

The Wiki article is about 2 graduate years of physics beyond my understanding. What is a good high-school rendition of his thought process: regarding his use of the "distributed capacitance and ...
3
votes
2answers
66 views

Propagation of mechanical waves in vacuum

It is known that, while electromagnetic waves can propagate in vacuum as they do not need a medium, mechanical waves (e.g. sound waves) cannot. However, vacuum has vacuum fluctuations, where (virtual)...
2
votes
1answer
110 views

What does Maxwell's equations predict for the propagation of EM waves converging to a point?

Maxwell's equations model EM radiation as propagating away from an accelerating charge. Suppose instead the propagation of this EM radiation is reversed and presented as a source-free boundary ...
0
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3answers
66 views

Polarisation of EM waves

My textbook reads 'The plane of polarisation of an electromagnetic wave is defined as the plane in which the electric field oscillates.' What exactly does this mean? I understand that an EM wave ...
0
votes
1answer
27 views

Optical fibers field analysis, $\phi$ dependence not considered

In optical fibers, the core (with $\varepsilon = \varepsilon_1$) is usually represented by a cylinder of radius $a$, whose axis coincides with the $z$-axis in cylindrical coordinates. The cladding is ...
2
votes
0answers
60 views

Is the speed of Magnetic field infinite?

My real question is: From Amperes law we know that there is no magnetic field outside of the coaxial cable because the magnetic field generated by the inner wire and outer shell are equal but in ...
0
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0answers
10 views

Resources for spin-stabilized magnets

I will be carrying out an experiment investigating the factors that effect the speed of a spin stabilized magnet. Can someone provide resources or articles that talk about/ have formulas related to ...
1
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2answers
40 views

Why does the electric field and not the magnetic field remains in the same direction after reflection from a medium?

I was reading up about reflection and transmission when an electromagnetic wave is normally incident on a surface. I came across this figure : My question is why is the direction of electric field ...
0
votes
1answer
24 views

EM- waves in anisotropic medium

When ElectroMagnetic waves from vacuum enter the anisotropic medium. If the $\epsilon$(permittivity) matrix is diagonal (with not all diagonal entries being equal). There'll be two waves in the ...
1
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1answer
45 views

Is the Electric and Magnetic field in an EM wave interacting in the same way static E and B fields?

Sorry by the title, I don't know how to ask this: What happens to a charge when some EM wave passes across it? If we have an EM wave with really low frequency, is this basically the same as having a ...
0
votes
0answers
17 views

Observing charge from non inertial frame

Charge radiates EMW when accelerated. But what if we are in non inertial frame and observe charge. Does it still emit EMW. (Another question: do we observe the magnetic effects of a rest charge if we ...
0
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0answers
10 views

Why does mode is confined to higher index material in the waveguide cross section?

I know the EM mode is confined to higher index material and its result can easily be seen after calculating the eigenmode within the cross-section of the waveguide. But having trouble to understand ...
0
votes
1answer
39 views

Is the electric field from light independent from the light magnetic field?

I was reading about antennas and I found an statement somewhat like this "loop antennas are more efficient compared to other antennas when close to the human body since the human body interacts more ...
3
votes
3answers
113 views

Light in classical electrodynamics

I am starting to learn elementary electrodynamics with Griffiths. In the book, he has shown the natural correspondence between light and electromagnetic plane waves. The problem that has agitated me ...