Propagating solutions to Maxwell’s equations in classical electromagnetism and real photons in quantum electrodynamics. A superset of thermal-radiation.

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Electro magnetic Wave? [duplicate]

I understand the fact that a static charge produces an electric field around it. I accept the fact(without questioning) that a moving charge produces a magnetic field. Question 1 : If a moving ...
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2answers
44 views

Is an x-ray maser possible?

I was wondering if lasers evolved from masers. They applied the same principles to a different wavelength. Would it be possible to create a maser at a higher wavelength, using x-rays, gamma rays, ...
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36 views

Scattering electromagnetic waves [closed]

I have a question about "Rayleigh Scattering efficiency", can you give me equations that describe it?
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1answer
28 views

Huygens principle and wave propagation

I have seen the following illustration online and had a brief lecture about Huygens principle. As far as I understood, it suggests that every point in a wavelet acts like a point source to wavelets, ...
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0answers
23 views

Is it possible to create a magnetic field camera that resolves magnetic fields to their source?

Is is possible to build a camera that is composed of an array of compasses that can resolve its magnetic field readings to sources outside of the sensor similar to the way an optic camera creates ...
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1answer
33 views

Name and unit for the amount of electromagnetic radiation

Is there a name or unit for the amount of electromagnetic radiation? By this, I mean the number of photons, or the number of photons emitted per second, of electromagnetic radiation. If you were to ...
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76 views

Dispersion of light in metals and the plasma frequency

I've been reading about the dielectric function and plasma oscillations recently and I encountered the following dispersion relation for EM waves in metals or in plasma (Is it correct to treat those ...
3
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1answer
131 views

Wavelength of electromagnetic waves [closed]

How can you determine experimentally the wave length of an electromagnetic wave having wave length in the visible range and that in the ultra violet range?
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1answer
21 views

Qualitative difference between bremsstrahlung and thermal bremsstrahlung

Hopefully this is an easy question. I hear the terms bremsstrahlung and thermal bremsstrahlung being used. However, I, incorrectly, thought that they were used interchangeably. So, what is te ...
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0answers
68 views

Why do our eyes only pick up electromagnetic radiation which has been classified as visible light?

My understanding: Electromagnetic radiation is carried via photons - which enter our eyes and activate receptors depending on the amount of energy the photons have when hitting them. At what point do ...
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38 views

How to detect transient X-ray?

I have a Mercury UV lamp (ENF-260C/FE) which is supposed to emitte UV light with wavelength of 254nm and 365nm (http://www.chescientific.com/ecat/Eng/spectroline.pdf). However it is found that during ...
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1answer
32 views

Why do higher frequency electromagnetic waves bounce of of smaller particles in the atmosphere but the lower ones dont?

I assume they have more energy but what is it more deeper and clearer than that that explains it?
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1answer
61 views

What is the trajectory of a photon moving through a vacuum?

Since electromagnetic energy is carried by photons and moves in forms of waves, does it mean that a single photon when propagating through space doesn't follow the straight path but instead always ...
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1answer
27 views

Low frequency video transmission

Can a video signal be transmitted for a short distance ($30\,\mathrm{cm}$) by a very low frequency carrier ? Here my concern is about frequencies $1\,\mathrm{hz} - 100 \,\mathrm{hz}$ . Transmission ...
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35 views

What are the properties of the electromagnetic radiation from a magnetron?

There are different modes of EM radiation. A bulb emits photons in a wide range of wavelengths and without polarisation. Radio waves are polarized modulated radiation. What is about the radiation ...
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0answers
15 views

Threshold voltage for townsend avalanche effect [closed]

I have an assignment to estimate the minimal voltage required for an avalanche effect to occur. All data I am given is electron energy (10eV) and pressure of the ...
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2answers
184 views

How in detail the rotation of the electric field component of light during transition through a polarizer takes place?

I ask "After a slit, are photons polarized?" and later found two answers for the question "Why does the electric field dominate in light?". From this two answers I have concluded or summarized, that ...
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29 views

When can I use Helmholtz equation for electraomagnetic wave

The complete Maxwell wave equation for electromagnetic field using the double curl operator "∇×∇×". Only when the transverse condition is hold, this operator can equal to the Laplace operator and form ...
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2answers
84 views

Do photons have a maximum density per unit area?

I've been sitting on this thought for a while, and I figure it's time to pass it off to someone more educated than myself. Consider the following hypothetical scenario: In a vacuum, we have six ...
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1answer
72 views

How do you detect the colors of a traffic light? (exam question) [closed]

I just took an exam where the question was: give three ways you can detect the colors of a traffic light given only a gray scale camera. You're allowed to use any optical devices. We learned about ...
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0answers
39 views

Can we prove that EM waves are transverse from Gauss's law of magnetism? [duplicate]

Can we use $ \mathbf B \cdot d\mathbf s=0$ to prove transverse nature of EM waves?
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32 views

Nature of Particle waves [closed]

My question relates to the properties of a single particle (for example purposes lets use a photon) Forgive me if this subject has already been answered by science, i am not aware that it has been ...
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2answers
77 views

How exactly do radio waves work?

So I understand that a radio wave is created by electrons oscillating in the antenna. But how does this create a radio wave? How are the electric and magnetic field "emitted" by the electrons? If you ...
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2answers
219 views

What symmetry is associated with conservation of Lipkin's zilch?

The 'zilch' of an electromagnetic field is the tensor $$ Z^{\mu}_{\ \ \ \nu\rho}=^*\!\!F^{\mu\lambda}F_{\lambda\nu,\rho}-F^{\mu\lambda}\,{}^*\!F_{\lambda\nu,\rho} \tag1 $$ given in terms of the ...
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1answer
104 views

Detailed form of light waves in vacuum and how to test it experimentally?

Consider a light wave in vacuum. Do the $\vec{B}$ and $\vec{E}$ fields have to be orthogonal to each other? Since you can add constants to a solution to Maxwell's equation it doesn't seem neccesary ...
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2answers
120 views

What about electromagnetic waves of power cables? [closed]

Edit I need to know about: low frequency electromagnetic waves in lower stages than radio waves. Here is picture of the region I'm interested in What can you say about frequency of power cables in ...
4
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1answer
366 views

Are there weak force waves?

In the same way as there are electromagnetic and gravitational waves that update the information on their respective field, is there an analogue for the weak and strong forces?
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58 views

Dependence of Color of Light on Wavelength?

Recently i saw a question here which asked "what does the color of light depend on as we percieve it?".Now some members answered that if you see an object from any other medium it appears the same ...
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1answer
17 views

How does this RSSI vs Distance equation work?

I came across this equation in a research paper, and can't seem to make sense of it. Let me give an argument for why it doesn't make sense, and perhaps someone can tell me where my flaw is? $$ ...
4
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1answer
102 views

Why don't I see green flames more often?

I was just thinking today that I usually see red flame, and have seen plenty of blue flame, but not green. My naive presumption for coloration of flames would suggest that I would see more green, so ...
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1answer
292 views

How do higher-order optical chiralities look like?

The optical chirality of the electromagnetic field is a conserved quantity, analogous to the energy density, linear momentum density, and angular momentum density, which describes how chiral the EM ...
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1answer
51 views

What is meant by infinite wavelength?

1#When an electromagnetic wave propagates in a plasma, with increase in plasma density the phase velocity ($v=\frac{\omega}{k}$) of wave increases. So at cut-off point $k=0$, and phase velocity ...
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1answer
71 views

What is the physical nature of electromagnetic waves?

I've been trying to work out what the physical nature of electromagnetic waves is, since I reasoned that given electromagnetic waves have wavelengths that are given in distance units, rather than ...
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0answers
24 views

How does mass affect the range of a nuclear particle?

Heavy particles such as protons and alpha particles of certain energy will lose all their energies in a definite distance in a medium, and this distance is called the range. The range is the distance ...
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0answers
41 views

Will matter vibrating at THz frequencies emit light?

Much like a magnet creating an alternating current when slid through a solenoid, will matter that vibrates at 500 THz create lightwaves? Here we are talking about taking an object which doesn't glow ...
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0answers
42 views

c “Propagation” in Weber Electrodynamics [closed]

The telegraph model of Weber-Gauss, relying on Weber's electrodynamics, modeled instantaneous action at a distance of the electric scalar potential (Coulomb potential) manifesting as propagation of ...
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0answers
16 views

Radio wave propagation path loss coefficient below 2?

We did a series of measurements of radio wave signal strength. The setup was between stations on top of flat roofs of neighbouring houses (with line of sight). We are interested in the path loss ...
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0answers
17 views

Concerning Thomson scattering

In https://en.wikipedia.org/wiki/Thomson_scattering, the intensity of the scattered light is diminished by the factor $\cos^2(χ)$. Can this angular dependence also be derived with quantum mechanics ...
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1answer
53 views

Dipole antenna $E$-field direction

I was looking up dipole antennas on Wikipedia, among other sites. I came across this animation: and was wondering why there wasn't any field lines in perfectly vertical direction. In the case of a ...
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2answers
27 views

Can you use Fourier transformations (or other) to read multiple superimposed barcodes?

If you printed bar codes on tracing paper/acetate etc. and then positioned several in front of one another, could you extract the individual codes from the aggregate overlaid image? I feel intuitively ...
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0answers
85 views

How did Maxwell conclude that light is an electromagnetic wave? [closed]

I was looking at the answers for "Why is light called an 'electromagnetic wave' if it's neither electric nor magnetic?", especially the answer by NikolajK that references a Wikipedia article and the ...
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1answer
57 views

Why phase velocity of light is slower in a dielectric than vacuum?

Why does light speed suffer a reduction when it passes through a homogeneous dielectric medium? I know my math says so, i.e.- a highly polarizable ($\chi$) medium is associated with high $\epsilon$ ...
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1answer
35 views

Accelerating electric charge

We know that massive bodies attract gas clouds that become ionized and the resulting acceleration can emit very high energy photons. In a case where a proton for example is undergoing prolonged ...
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1answer
94 views

If photons have mass then how can they travel at speed of light? [closed]

Anything that has mass must be slower than speed of light. If they are travelling at speed of light they must contain infinite energy which should be able to destroy everything, clearly thats not ...
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27 views

Confusion about radioactivity

The following question is from General Problems on Physics by I.E Irodov 6.220. Find the decay constant and the mean lifetime of $^{55}\operatorname{Co}$ radionuclide if its activity is known to ...
4
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2answers
104 views

Can wifi signal reception be improved by opening a door? [closed]

Use Case A wifi user is in a different room than the router. The computer is having a hard time connecting and receiving the wifi signal. Engineering Question Can the wifi signal from the router to ...
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0answers
45 views

Can TE and TM modes propagate together in a waveguide?

I recently came to understand the TE and TM modes. As it is defined that E=0 for transverse electric and vice-versa. I have a few basic questions in mind which I thought to ask in one thread only. ...
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1answer
34 views

FWHM increase with energy (gamma spectra)

Below I have two plots from a gamma spectrum which I've been analyzing. The first plot is between a low energy range, the second between a significantly higher energy range. It is clear that the FWHMs ...
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2answers
80 views

How is frequency related to kinetic energy?

Does producing higher frequency waves require more energy than their low frequency counterparts with same amplitudes? For example, in electronics, would a 500 kHz wave require higher voltage to ...
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0answers
50 views

What does matter wave oscillate? [closed]

We know by Maxwell equation, light is an Electro-magnetic wave, the light is oscillating the magnetic field and electric field and propagate Sound will oscillate the air, water, or whatever and ...