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

learn more… | top users | synonyms (1)

0
votes
0answers
39 views

What is the relationship between the electric field E and the magnetic field (aka magnetic flux density, magnetic induction) B of a single photon? [duplicate]

I'm looking for a formula for light, for example with 660 nm wavelength, which describes the maximum of the amplitudes for the wavelength of the electric and the magnetic field of the propagating ...
0
votes
2answers
366 views

The Quantization of Photon Energies

Despite Planck's constant being in $E=hf$, it would appear to me that energy is still not discrete, as frequency can be an fraction of a Hertz that one wants. How does this imply that electromagnetic ...
2
votes
1answer
207 views

Would there be EMF induced in our body due to electromagnetic radiations?

The experiments of innovative Faraday and Joseph Henry in USA, conducted around 1830, demonstrated conclusively that electric currents were induced in closed coils when subjected to changing magnetic ...
2
votes
1answer
62 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 ...
2
votes
2answers
257 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 ...
1
vote
1answer
29 views

Is it possible that matter/antimatter collisions emit resonance frequencies of H/He?

Is it possible that matter/antimatter collisions emit resonance frequencies of H/He? I am researching a high energy phenomenon that occurs between the frequencies of 1200-1580 MHz. This come from a ...
14
votes
4answers
1k views

Is the frequency of light restricted?

What are the factors that limit the frequency of light? Can it have wavelengths ranging between zero and infinity?
2
votes
1answer
50 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?
1
vote
1answer
30 views

transfer of electricity through electromagnetic waves

Is it possible to transfer electricity from one place to another without the help of physical wires.
6
votes
3answers
643 views

Why can't light penetrate solid objects?

Light is combination of perpendicular electric and magnetic fields, since electric fields penetrate a conductor, why can't light travel in them? I think my argument does sound stupid, but I can't ...
2
votes
1answer
42 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. ...
0
votes
0answers
20 views

Refractive index variation with colors [duplicate]

To explain the spectrum formation in the prism, my teacher said that different colors have different speeds in a medium, so, refractive index is different for all. So, angle is different. But I don't ...
19
votes
5answers
2k views

Does a charged particle accelerating in a gravitational field radiate?

A charged particle undergoing an acceleration radiates photons. Let's consider a charge in a freely falling frame of reference. In such a frame, the local gravitational field is necessarily zero, ...
2
votes
1answer
53 views

Why does the speed of the Electromagnetic wave in the material depend on the frequency of the wave where as they are constant in vacuum (freespace)? [duplicate]

I am confused on why would the propagation speed of any EM waves at ANY frequency is constant in the free space (vacuum) but they seem to disperse in any other materials as the propagation speed of EM ...
12
votes
1answer
474 views

Why is Huygens' principle only valid in an odd number of spatial dimensions?

Apparently Huygens' principle is only valid in an odd number of spatial dimensions: http://mathoverflow.net/a/5396/21349 Huygen's principle in curved spacetimes Why is this? [EDIT] This is ...
2
votes
3answers
292 views

How does the movement of electrons produce radio waves?

I'm mostly wondering about radio frequencies. I understand that voltage is the movement of electrons, and that the antenna acts as a light bulb, emitting at radio frequencies, following the reverse ...
3
votes
2answers
134 views

Huygen's principle in curved spacetimes

Does Huygen's principle hold in even dimensional (2m+1,1) curved spacetimes, or are there certain necessary conditions for it to hold? In other words, if I have Cauchy data for a field satisfying the ...
10
votes
4answers
2k views

Is it possible to shield a camera so as to record from the inside of a running microwave oven?

Would it be possible to create shielding for a camera, allowing it record food being cooked from the vantage point of the inside of a consumer microwave oven without the camera being damaged? ...
5
votes
2answers
219 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 ...
4
votes
3answers
98 views

In scattering, how does a particle 'know' which direction it is being illuminated from?

In scattering experiments, for example light scattering, the scattering strength from different sized particles is depicted as below. What I can't understand is: how does a particle know which ...
3
votes
2answers
55 views

Why is radiation for an ultrarelativistic charge zero on axis?

I attribute it to the fact that for an ultrarelativistic charge the field is contracted and essentially there are only fields in the transverse direction and nothing longitudinally (wrt the charges ...
3
votes
0answers
97 views

Free charge movement in an electric field - including bremsstrahlung

Let us imagine a free, negatively charged object that is in rest and placed in an elecric field of a point positive charge. The positive charge has a huge mass and cannot move, so we consider only the ...
3
votes
2answers
92 views

Physical reason why (hot) objects glow? [duplicate]

Every object at a non-zero temperature radiates light, i.e. it glows. (Is that called blackbody radiation?) What is the physical reason to this? Is it because more heat implies that the atoms ...
4
votes
10answers
2k views

Why do we think of light as a wave?

I've read that light travels in a straight line and has a wavelength of 400nm to 700nm. But I don't understand why does it have a wavelength and what creates its wavelength? I agree with the concept ...
17
votes
3answers
4k views

How would an X-ray scanner identify a mirror?

A mirror is under normal circumstance 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 ...
0
votes
0answers
13 views

Where does $R/\gamma^3$ come from in relativistic E&M?

I am starting to read many papers on electron beam physics; more specifically its motion in a magnet i.e. curved motion. The term $R/\gamma^3$ comes up a lot, but I don't know where they are coming ...
-4
votes
1answer
94 views

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

"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 ...
1
vote
1answer
48 views

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

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 ...
4
votes
1answer
550 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 ...
4
votes
2answers
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. ...
2
votes
4answers
1k 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 ...
4
votes
1answer
142 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 / ...
0
votes
0answers
49 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) ...
1
vote
3answers
325 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 ...
3
votes
3answers
64 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 ...
3
votes
4answers
635 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 ...
5
votes
2answers
392 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 ...
3
votes
3answers
214 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 ...
2
votes
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 ...
6
votes
3answers
574 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 ...
1
vote
3answers
122 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 ...
2
votes
1answer
820 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 ?
0
votes
2answers
131 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 ...
4
votes
2answers
464 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 ...
3
votes
3answers
1k 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 ...
3
votes
2answers
200 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?
10
votes
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 ...
1
vote
2answers
49 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 ...
3
votes
5answers
321 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 ...
3
votes
1answer
79 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?