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

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46 views

Radiation emission and absorption

Any object can emit and absorb radiation and the power of emission can be represented by the Stefan-Boltzmann law: $$P=A\epsilon\sigma T^4$$ In many texts the net power radiated is the difference ...
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61 views

Massless particles and the speed of light - New? Theories of existence [on hold]

"The best understanding we have is that it [light] is a disturbance in the electromagnetic fields of charged bodies." http://einstein.stanford.edu/content/relativity/q212.html This is a link to the ...
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1answer
41 views

If light was able to pass through a wall, would the wall be invisible to the human eye? [on hold]

In addition, to get light to other side of the wall, could it be converted to radio waves and then back to light waves? Edit: My idea was if there was a special material that was painted on both ...
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1answer
536 views

Two photons transition

if an atom in its ground state is coupled to an electromagnetic field it can absorb a photon if the EM field contains one with the right frequency. These transitions depends on $⟨f|H_i|i⟩$ (from ...
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4k views

How would an X-ray scanner identify a mirror?

A mirror is normally used to reflect Electromagnetic radiation also known as photons (light) and in airport security or medical facilities, they use X-rays to detect anomalies inside objects or bodies ...
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2k views

How does the grid on the microwave oven window prevent microwave radiation from coming out?

If I look through the microwave window I can see through, which means visible radiation can get out. We know also that there is a mesh on the microwave window which prevents microwave from coming out. ...
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5answers
991 views

How can we detect X-rays?

I know that X-rays can be detected by various ways, like ionizing of air particles. Is there a way to detect X-rays,which are photons, by detecting? Can something absorb the energy of the X-rays and ...
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1answer
47 views

Could airport security devices detect differences between printed and written documents?

If airport security scanners of any kind (xray, thermal, whatever else they use) looked at two items: A printed paper textbook The same printed paper textbook into which we have inserted a regular ...
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1answer
127 views

Does any lower frequency electromagnetic radiation naturally reach us from the Sun?

I am not sure whether the sun originally emits everything in the electromagnetic spectrum, (whatever the relative strengths of each portion might be), but I do read that many waves, including gamma / ...
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21 views

States that Wave-length, Pressure and Temperature describe [on hold]

I have two doubts : 1 - Can wave-length of light emited by some light-source ( like a black-body ) take arbitrary distance values ( any value in the set of real numbers ) ? 2 - Pressure is the name ...
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44 views

Mathematical formalism to include wave and particle perspectives of light

Does the exist any mathematical formalism (model) describing the behavior of light and incorporating its particle character (divisibility, quantization) and wave character? (i.e. quantized wave model) ...
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3answers
315 views

Does the intensity of dipole radiation fall as $1/r^2$ or $1/r^3$?

I have seen this derivation: I want to estimate what is the intensity of the electrical field as function of $r$ the distance from the radiated source ? I think it is can modled as pointed source ...
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1answer
49 views

phase difference between incident plane wave incident on a dipole and radiation fields from dipole

i have an incident plane wave and a dipole, consider that plane wave incident on dipole. at this moment what happen for dipole ? we know that after incident of plane wave on dipole, the radiation have ...
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3answers
55 views

Unpolarized Light

Suppose I had a ray of unpolarized light, and I was sitting inside the beam and looking at the electric fields oscillating, then , if I am looking at a point how would the oscillations look like? I ...
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1answer
65 views

Blackbody and standing waves

I'm reading articles about black body radiation and why classical mechanics fails to explain it. My question is: Why do EM waves have to be standing wave in a cavity?
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4answers
549 views

Do Electromagnetic Waves really propagate through continuous Induction?

I've often seen it said that in an Electromagnetic Wave the changing Electric Field component creates the Magnetic Field Component and the changing Magnetic Field Component in turn creates an Electric ...
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2answers
376 views

Does light really “travel”?

From what I've so far understood about light, a photon is emitted somewhere and after some time it's absorbed somewhere else. Have we had experiments that confirm the path taken or something akin to ...
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3answers
88 views

Do photons interact only with single particles or can a single photon be absorbed by 2 or more particles simultaneously?

Say I have 100 particles in a vacuum that are spread out such that their movement caused by a time variant electromagnetic field does not have an effect on each other. That is the particles can not ...
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3answers
180 views

How to understand “accelerating charge radiate” using intuition? [duplicate]

While I know that accelerating charges produces EM radiations (at least in lots of cases), most discussion about this matter only focuses on which kind of situation will emit EM radiations and which ...
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2answers
3k views

Microwaves vs Gas or Electric Coil heating of a water boiler in a typical household

Wouldn't it be more energy efficient and or safe to use microwaves to heat our home's water boiler instead of using dangerous gas or hot electric coils that could catch other things on fire? I'm kinda ...
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3answers
546 views

How is temperature related to color?

I spent some time studying about temperatures and color of objects. It turns out that as we heat something it turns to red, then yellowish white and if we heat it more it turns to bluish-white. Like ...
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2answers
2k views

Real and imaginary parts of dielectric constant vs refractive index?

So for a complex dielectric constant $\epsilon = \epsilon_a + i\epsilon_b$, the wave vector and index of refraction are related to it through $k = \frac{\omega}{c}n$ and $n = \sqrt{\frac{\mu ...
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3answers
100 views

Is the Speed of Light an universal spacetime constant, the velocity of electromagnetic waves, or of photons?

This question has been touched tangentially by What's a better phrase than "speed of light" for the universal spacetime speed constant? and Could light travel more slowly than the ...
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1answer
88 views

What is absorption of an electromagnetic wave?

Can any one explain the absorption/transmission/reflection of electromagnetic waves in the wave form? It is generally said that the atom absorbs/reflects/transmits photon. But can this phenomena be ...
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1answer
507 views

Physical meaning of Maxwell's equations and origin of EM waves

Is it possible to describe the physical meaning of Maxwell's equations and show how they lead to electromagnetic wave, with little involvement of mathematics ?
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2answers
92 views

What is the difference between light and visible light? [duplicate]

After watching a few videos on light and electromagnetic radiation, I am a little confused. The way things are explained, is that light is just the same as electromagnetic radiation I thought this ...
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1answer
101 views

Probability density of detection of collinearly emitted photons in two detectors

Update: As proposed by @dmckee, I added equation numbers and improved the display of some equations. The answer by @Trimok inspired me to look at coordinate systems which are not specific to the ...
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2answers
447 views

Do x-rays and gamma rays also contain photons like visible light does?

Do x-rays and gamma rays also contain photons like visible light does? If so, then what makes photons of visible light and other waves different? The rest mass of a photon is zero, but as it moves at ...
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3answers
561 views

Temperature behavior over time of black or white cars in hot, sunny regions

How does the color of a car influence its inner temperature change over time when parked outside in windless, hot and sunny regions? I know what's the common idea about that: black cars are supposed ...
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1answer
113 views

Can we draw analogy between em power flow through free space and ac power flow through a transmission line?

Knowing that the free space has a characteristic impedance (which is purely resistive, measured in ohms) I was wondering if I can model the free space as an infinitely long transmission line- ...
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2answers
169 views

Why doesn't the magnetic field polarize when polarizing light?

If the magnetic field doesn't polarize does it follow the electric field path of propagation? or does it vanish?
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1answer
77 views

Admixtures of longitudinal and timelike photons!

In the quantization of electromagnetic field the physical states $|\psi\rangle$ are found to obey the following relation: $[a^{(0)}(k)-a^{(3)}(k)]|\psi\rangle=0$ It is explained as the physical ...
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3answers
2k views

Why is it necessary for an object to have a bigger size than the wavelength of light in order for us to see it?

I keep hearing this rule that an object must have a bigger size than the wavelength of light in order for us to see it, and though I don't have any professional relationship with physics, I want to ...
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1answer
56 views

Far Field Diffraction of EM waves: what does the zero frequency signify?

If you have a system of independently radiating electrons/point-charges, the far field distribution of the EM waves can be approximated by the fraunhoffer diffraction integral, or simply by the ...
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2answers
41 views

On the shape of magnetic and electric fields in an electromagnetic wave

Electromagnetic waves are generally depicted like this: Where the electric fields and magnetic fields exist in the planes perpendicular to the direction of propagation. I also realize that as the ...
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5answers
228 views

How is a vacuum able to propagate light?

We say that sound waves need a medium to propagate and we know that light doesn't need such a thing. But is that really how that works? There's no such thing as "nothing" according to Quantum ...
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2answers
242 views

Which cyan colored line is produced in the Thomson e/m apparatus?

Related: Which green spectral line(s) are emitted in a Thomson tube? After reading Lisa Lee’s OP on an electron deflection tube, although she had some misunderstandings on its operation, I still ...
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1answer
47 views

Earnshaw Theorem for ionic solids

Is a single molecule of sodium chloride (say) or a cluster of molecules of NaCl unstable, although macroscopically NaCl is in fact, stable? How can I reason this based on Earnshaw's theorem?
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1answer
57 views

Would white light waves act as same as monochromatic waves in double slit experiment?

Would white light waves act as same as monochromatic waves in double slit experiment? If not, what pattern would be seen on the screen?
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1answer
39 views

AM vs FM radio under bridges

I know what the difference between AM (Amplitude Modulation) and FM (Frequency Modulation) radios is. However, I noticed that when I drive under a bridge while listening to a station on AM, it just ...
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1answer
25 views

transfer of electricity through electromagnetic waves

Is it possible to transfer electricity from one place to another without the help of physical wires.
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26 views

Quick question about absorption of waves

Suppose a plasma has characteristic frequency $\omega_p$. Since $$n = \sqrt{\left(1-\frac{\omega_p^2}{\omega^2}\right)} $$ For $\omega<\omega_p$, the refractive index will be imaginary - which ...
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1answer
38 views

Import of Celestial Effects on Satellite Radio Interference

Some internet (among other) infrastructure comprises satellites, which beam communications in radio frequencies. These satellites, to ground observers, appear as very small solid angles in the sky. ...
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2answers
75 views

Would it be possible to detect nuclear explosion on exoplanet?

How strong would have to be nuclear explosion on exo-planet that orbits some other star for it to be detectable outside of that system. Or it would be impossible due to amount of radiation coming from ...
0
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1answer
53 views

Electromagnetic radiation and black body radiation

I was taught today that the Electromagnetic wave Theory is unable to explain black body radiation. The example that was given to me: When a metal is heated, it emits different frequencies of light as ...
4
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1answer
61 views

Is the body's exposure to an x-ray equal to an airplane trip across the country?

I have heard numerous times when getting x-rays, MRIs, CAT Scans, etc. that each one is equivalent to a cross country airplane trip. Disregarding the different types of radiation as asked in this ...
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4answers
672 views

Magnetic fields and gravitational waves. How far do they reach?

I read that magnetic fields perpendicular to a current shoot out and expand all the way to infinity. Additionally a gravitational wave, no matter how small will also expand to infinity at the velocity ...
5
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3answers
668 views

Why aren't all photons virtual particles even in the “vacuum” of empty space? [duplicate]

I'm thoroughly confused about the nature of electromagnetic radiation. Light is supposed to exhibit both wave and particle characteristics. But does that mean that it is both a wave and a particle or ...
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4answers
704 views

Can an LC oscillator be used to generate visible light?

The LC oscillator is most commonly used to generate radio waves for practical use and the frequency $\omega$ of the LC oscillator equals that of the electromagnetic wave so produced. So, can they in ...
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2answers
210 views

Impossible microwave interference?

I was doing a microwave experiment with the following set up: there is a Gunn diode which emmits microwave radiation and a receiver (both work with polarised light). The strange thing is that when ...