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

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How does electromagnetic radiations penetrate?

I am reading about the discovery of subatomic structure which includes all these things radioactivity, alpha rays, gamma rays, x rays et cetera. I read that electromagnetic radiations are energy ...
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2answers
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1answer
95 views

Why are electric and magnetic fields perpendicular in an electromagnetic wave?

I want to know why electric and magnetic fields are perpendicular in an electromagnetic wave and what would happen if they weren't.
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1answer
41 views

Radiation frequency from an accelerated charged particle

My understanding is that a charged particle, when accelerated emits EM radiation. In a situation where a charged particle is briefly accelerated in a straight line it should produce a propagating ...
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1answer
111 views

What is the nature of the magnetic fields? [closed]

In this question, I am hoping to find out if there is an explanation to the magnetic hidden forces. In other words, what causes these fields? Is there any suggested theory, or any confirmed ones ? ...
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1answer
53 views

How to visualize electromagnetic waves?

Can someone please explain to me how to visualize an electromagnetic wave in 3D space? I have struggled for a long time now trying to understand how a WiFi signal could reach a device if it looks like ...
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2answers
35 views

How is it possible to even develop any current in an inductor?

Potential difference across an inductor (ie p.d. between current exit point and current entry point) is given as $$V= -L\frac{di}{dt} -iR,$$ where $L$ is the inductance of inductor and $R$ is its ...
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1answer
58 views

Vacuum chamber that prohibits EM wave propagation

Is it possible to create a vacuum chamber (something like vacuum tube) in which EM wave propagation is prohibited and EM radiation does not exist at all?
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1answer
72 views

How do integral representations of $\mathbf A$ and $\Phi$ satisfy Lorenz condition?

The following are the integral solutions of the potentials, obtained from the retarded potentials (by a Fourier transform): $$\mathbf A (\mathbf r) = \frac{\mu_0}{4\pi}\int_V \frac{\mathbf J (\mathbf ...
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0answers
6 views

does colour of compound affects the specific optical rotation at defined costant temperature and wavelength?

If analyte has a defined method of analysis for the Specific optical rotation. is it possible a change in specific optical rotation due to change in colour of same substance?
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7answers
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What's the difference between mechanical and electromagnetic waves? [closed]

I have a life science degree and even worked in research for a few years. So I feel I should be able to answer this question for myself, but yesterday my daughter blindsided me by asking why, if sound ...
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1answer
58 views

Light waves and water waves

I have an idea and i would like to have more information: If I drop a stone in the water some rings or waves will appear. Those rings are made of water and are behaving that particular way because of ...
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4answers
127 views

What carries electric field through space?

A stationary charge "creates" a constant (but not uniform) electric field around it, and a moving charge "creates" a variable electric field around it. What "carries" the information about the ...
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2answers
43 views

What is the actual meaning of magnetic field and electric field in Electromagnetic waves?

I know that electromagnetic waves are composed of electric field and magnetic field but I don't understand what magnetic field is. Would you help me understand its physical meaning? What is the ...
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33 views

What is filtered through the linear polarization of EM light? E field, B field or both?

I know that for EM waves (i.e sunlight) for any E wave in any direction, there is B field perpendicular to it. However, when we pass that EM wave through the linear polarization filter, what actually ...
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0answers
69 views

Do all particles have radiative transitions?

Everybody knows that excited electrons can emit photons upon relaxation. A nucleus too (which is not an elementary particle), can be in an excited state and emit gamma rays upon relaxation: (source) ...
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0answers
33 views

Is an “underwater” submarine affected by a nuclear bomb exploding above the water? [duplicate]

I've just read Would being underwater help survive a nuclear bomb?. Submarines are way more armored and far from the surface than a human body (https://en.wikipedia.org/wiki/Submarine_depth_ratings), ...
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3answers
62 views

Do white light generated by light bulb also have significant Infrared intensity?

I am planning to obtain near infrared light for a project. Instead of producing the infrared myself, I thought it might be easier to use something inexpensive and commercially available. That's why I ...
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0answers
46 views

Phase noise measurement with an IQ mixer

I have a question regarding a measurement scheme of phase noise that I'm trying to implement. The idea is that I have two identical signal generators (I actually do) that generate a sinusoidal voltage ...
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1answer
95 views

Converting Stokes Parameters to Jones Vector

How do you convert a Stokes vector into a Jones vector? I am only concerned about fully polarised light, and I need to convert the Stokes parameters (or the azimuth and ellipticity angles) as measured ...
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1answer
92 views

Does the complex conjugate of a vector have the same direction as the vector?

Looking at reflected and transmitted optic waves, the $\overset{\rightharpoonup }{E}_t$ vector is always perpendicular to $\overset{\rightharpoonup }{k}_t$ (as seen in the attached image). So $\...
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1answer
36 views

Evanescent waves in Vacuum

I would like to know why evanescent waves are not possible in pure vacuum? Indeed, we have $$ k^2 = (\frac{\omega}{c})^2 $$ in vacuum, so we could have for example : $$ kx^2+ky^2+kz^2=(\frac{\omega}{...
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0answers
67 views

Do gravitational waves have field components like electromagnetic waves?

One way I've been led to understand electromagnetic waves (and I accept that this might be a misconception I have) is that they 'self propagate' through empty space by virtue of the wave consisting of ...
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0answers
12 views

System of two perfect isolated bodies and infrared death

What is the theory about a system of two bodies, which is perfect isolated from the environment? Take it as a Gedankenexperiment, where the two bodies are not perfect reflectors but the isolating ...
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3answers
97 views

Effect of Gravitational Waves on light?

We all know about the gravitational lensing effect. From the analogy of fabric of space time used to explain this concept to laymen like me, i understand that light follows the curvature of spacetime. ...
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3answers
123 views

Can light escape a black hole? [duplicate]

I heard that a black hole is not black because it's escape velocity is greater than or equals to the speed of light. But instead it is black because the light that gets emitted from a black hole gets ...
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0answers
21 views

Determination of temperature from electromagnetic emissions

The actual measured radiation intensity at different frequencies varies significantly from the ideal theoretical Planck curve. For example, here is the result of a typical laboratory measurement at ...
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1answer
56 views

Concentrating the Sun with mirrors facing each other

What will happen if the sun is concentrated by directing sunlight to mirrors that are facing each other? i know that mirrors absorb light and dont reflect 100% but will the efficiency increase due to ...
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2answers
117 views

Does light have mass? [closed]

Does light have mass? If yes, will it exert force? If no, then how are light particles are travelling at light speed? If light doesn't have mass how is it attracted by gravitational force (black holes)...
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1answer
74 views

Temperature from gamma rays?

I was reading about gamma ray bursts and read something along the lines of 1 MeV gamma rays corresponding to a fireball above 2 billion degrees Celsius. How do scientists get temperature from that? ...
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3answers
56 views

Radiation due to current

Generally we equate change in potential energy to change in kinetic energy but in case of a charged particle like electron this is inconsistent. Consider a case: An electron(of charge e)from rest is ...
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3answers
117 views

Where do the energy and momentum come from when light is perfectly reflected on a surface?

If you send a light beam to a surface which reflects the light perfectly I would say that on the surface is put a force of the light so the surface moves backwards. But where does that energy comes ...
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48 views

Have gravitational waves any effect on the electromagnetic waves in interferometers?

I am not into general relativity, but the explanation of how an interferometric gravitational antenna works is generally pretty basic. In the recently published paper announcing the detection of ...
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24 views

How will EM waves behave if they are made to pass through a region of intense magnetic/ electric field?

My question is exactly what the title says. I think they should not be affected as photons are uncharged. But shouldn't the oscillating Electric and Magnetic fields be affected by the electric/ ...
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76 views

Covering the whole world in an EMP

I recently thought about shutting down the whole worlds electronics, and naturally ended up with an EMP. I know that EMPs are generated when nuclear bombs explode, but nuclear bombs have some unwanted ...
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2answers
54 views

Is there an instrument that measures the Frequency of light directly

Is there an instrument that measures the frequency of light DIRECTLY? By "DIRECTLY" I mean without using any properties of the Wavelength.
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Non-standard representation of the free electromagnetic plane wave

The usual representation of a free electromagnetic wave in vacuum looks like this: The blue parts are the local electric field, while the green parts are the local magnetic field. The circularly ...
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43 views

Collimation and the inverse square law

This is my understanding of how the inverse square law applies to collimated light, and specifically laser light, since AFAIK it's the only light that can be collimated with any accuracy thanks to ...
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0answers
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Can Obstruction of EM waves itself obstruct change in field?

Let us continue to accelerate a particle P, up and down: between two points X,Y in space(and, say, always in a symmetric manner relative to X,Y). Now, as I know, we'll be continuously dragging the ...
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1answer
43 views

Plane waves intensity

Our professor said that a plane wave has the same intensity in the plane perpendicular to it's propagation. I can't really make sense of how that is possible. I mean, shouldn't the intensity decrease ...
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0answers
48 views

Will the photon wavelength fluctuate in the presence of a gravitational wave?

The microwave background is due to the expansion of the Universe where the wavelengths of radiations are stretched by spacetime. As in the LIGO experiment, in the presence of gravitational wave, ...
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0answers
19 views

How to think about Ripple and Noise in circuits

Say you have a AC to DC power supply. If you were to hook an oscilloscope up you would see noise occurring. Some of it would appear to have a regular frequency in Khz or Mhz. Would this put off EM ...
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25 views

To which extent is the treatment of nuclear multipole radiation by the means of a classical electromagnetic field valid?

In the treatment of nuclear multipole radiation, for example in the context of nuclear gamma decay, it is standard, at least at the elementary level, to formalize the electromagnetic radiation as a ...
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2answers
42 views

Magnetic induction to generate EM waves

Let's say that I create a time varying magnetic field. This field then cuts a conducting circular loop normally. The loop has two protruding wires. Will the protruding wires emit EM waves? I ...
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2answers
135 views

How many photons are there in free space on average

Estimates of the amount of for example "dark matter" are of interest to the cosmologists. However, I have never seen an estimate of how many "free" photons could be speeding about in the known ...
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0answers
32 views

optoelectronics-smallest wavelength of light

Sorry this maybe a stupid question , but i need to know: A few minutes ago i have read an article about optoelectronics: worlds first optical single atom switch The writer of the article claims:"...
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39 views

What does this coordinate transformation in the Wave equation mean?

My tutor derived the following of which I do not understand the transformations (2.1) and (2.2): $$\Delta\vec{E} - \frac{1}{c^{2}} \frac{\partial^{2}\vec{E}}{\partial t^{2}} = \frac{4\pi}{c^{2}} \...
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1answer
83 views

What do we mean by wavelength of any electromagnetic wave?

What do we mean by wavelength of EMW? Wavelength of oscillating electric field or the oscillating magnetic field? Or is it that both the electric and magnetic field waves have same wavelength? If ...
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0answers
44 views

Implications for measurement of an initially localized free particle's wavefunction spreading out to infinity?

So, I have been attempting to wrap my head around what happens to a free particle that is initially localized to one spot. It seems that due to their different frequencies, the particle's wavefunction ...
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2answers
185 views

Why does a laser beam stay collimated?

I am looking for a simple way of explaining the collimation of a laser beam. The typical discussion of the two slit experiment of quantum theory relies heavily on the Huygens principle. Its ...