Questions tagged [electromagnetic-radiation]
Propagating solutions to Maxwell’s equations in classical electromagnetism and real photons in quantum electrodynamics. A superset of thermal-radiation.
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Is there a substance which can pass both IR and UV radiations?
I have been thinking about this for a while. A quartz prism allows UV Radiation to pass. A rock salt prism allows IR radiation to pass. Glass absorbs both.
Is there something, that is, a substance to ...
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Is there an IR-camera-detectible color that can be the coat for a material to transfer the material heat by emitting into the space? [closed]
If we see a material it is coloured in a color that our brain could easly recognize. But when we look at it by the help of an IR camera it could also be coloured and if two materials have same ...
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How to use dipoles to enforce the boundary conditions for a spherical dielectric with complex permittivity
I want to impose an electric and magnetic field on a spherical dielectric of radius $ R $ and relative permittivity $\epsilon_r=\epsilon'+i\epsilon''$. Say the fields are slowly-varying (like a plane ...
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Stefan-Boltzmann's law independence of surface density
One thing about Stefan-Boltzmann's law didn't make sense to me is that the radiated power density is independent of the particle density of a surface. It seems like things have to cancel out amazingly ...
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Link between photon helicity and polarization of $A^\mu$ electromagnetic potential
From Wigner theorem we know that the irreducible unitary representation of the Poincarè group for massless and spin 1 particle is labelled by the momentum $p_\mu$ and the two possible helicity $+1,-1$ ...
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Does electric and magnetic field from electromagnetic radiation are 2D based? [closed]
I'm getting into physics, specially in electromagnetism.
When we're talking about electromagnetic radiation. Does it has a 2D shape when it's propagating through space?
Does Maxwell's equations ...
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Can we catch signals from a cellphone using an external device? [closed]
What if someone stole em waves from our mobile devices to listen to our conversations or get our OTP. Whatever encryptions they have they are just EM waves innit and they cannot be propagated only in ...
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How well does a cavity with a hole approximate a black body?
Cavity with a hole is a frequently cited approximation to a black body (more precisely, it is the hole that is the black body here):
Is there a simple estimate of how well such a cavity approximates ...
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Diffraction when the wavefront is not parallel to the plane
I am studying Feynman's chapter on the origin of the index of the refractive index (see this link).
If I am not mistaken, what he does is to prove that when a wave enters a medium (modelled as a ...
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Dipole antennas and the $B$ field
A dipole antenna responds to the electric component of a EM wave. Does the magnetic component of a EM wave have any effect on the performance of a receiving dipole antenna?
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Will an electron release energy when it is added into an atom for which electron affinity value is negative (endothermic)?
According to my understanding, when an electron is added into an atom, it emits energy in the form of photons because it is a form of de-excitation or relaxation. This is when electron affinity will ...
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How does light beyond the visible spectrum relate to color theory?
Like if you put a red spotlight and a blue spotlight on the same area, the light ends up magenta. And if your light is purple and you have a yellow chair, the chair will appear black because the ...
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Why is the length of a Faraday cage's lattice relevant to what wavelengths it blocks?
I believe the title is self-explanatory. I see a similar reasoning pop up often in other areas where EM radiation is being manipulated, e.g. lasers, radars, radio telescopes and so on.
The wavelength ...
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What actually happens when light goes into a waveguide?
I have only dealt with a rudimentary theoretical treatment of how light propagates inside a waveguide, such as those available in Griffiths.
One thing bugging me is that I still do not know how ...
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About the notation for TEM waves
I just came across this article where the term "$\mathrm{TE}_{101}$ microwave mode" is mentioned. Other than the basics of TEM waves which I learned in Griffiths, this is the first time I ...
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