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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Does a constantly accelerating charged particle emit EM radiation or not?
The Abraham-Lorentz force gives the recoil force, $\mathbf{F_{rad}}$, back on a charged particle $q$ when it emits electromagnetic radiation. It is given by:
$$\mathbf{F_{rad}} = \frac{q^2}{6\pi \...
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Why one should follow Snell's law for shortest time?
whenever two media and two velocities are involved, one must follow Snell's law if one wants to take the shortest time.
Why snells law must be followed to travel diffrent media in shortest time?
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Is the electromagnetic spectrum discrete?
I'm just starting to learn physics and I have a question (that is probably stupid.)
I learned that energy levels that the bound electron can have are discrete. I also learned that when an electron ...
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Amplitude of an electromagnetic wave containing a single photon
Given a light pulse in vacuum containing a single photon with an energy $E=h\nu$, what is the peak value of the electric / magnetic field?
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Explain how (or if) a box full of photons would weigh more due to massless photons
I understand that mass-energy equivalence is often misinterpreted as saying that mass can be converted into energy and vice versa. The reality is that energy is always manifested as mass in some form,...
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Why does wavelength change as light enters a different medium?
When light waves enter a medium of higher refractive index than the previous, why is it that:
Its wavelength decreases?
The frequency of it has to stay the same?
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Is there an infinite amount of wavelengths of light? Is the EM spectrum continuous?
The electromagnetic spectrum is a continuum of wavelengths of light, and we have labels for some ranges of these and numerical measurements for many.
Question: Is the EM spectrum continuous such that ...
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How do mirrors work?
My physics professor explained to me that electromagnetic waves are consisted of two components - electric and magnetic - which cause each other.
Which part of the mirror actually reflects the wave?
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Scattering of light by light: experimental status
Scattering of light by light does not occur in the solutions of Maxwell's equations (since they are linear and EM waves obey superposition), but it is a prediction of QED (the most significant Feynman ...
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Why does the refractive index depend on wavelength? [duplicate]
Why do different wavelength get impeded more or less when in different materials? Moving with the same speed, but a longer physical distance would imply that the fields oscillate less times in the ...
user24082
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Black body vs. Thermal radiation
I am seeking clarification of the following terms:
Black body radiation
Thermal radiation
Thermal light source
At the first glance, the first two are the same thing, and they are the radiation ...
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If you view the Earth from far enough away can you observe its past?
From my understanding of light, you are always looking into the past based on how much time it takes the light to reach you from what you are observing.
For example when you see a star burn out, if ...
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Are magnetic fields just modified relativistic electric fields?
Feynman's Lectures, Volume 2, says that the electromagnetic force is invariant in any reference frame, and the magnetic force in one frame becomes the electric field in another.
And Wikipedia says:
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What is the minimum wavelength of electromagnetic radiation?
As a first approximation, I don't see how a wavelength of less than 2 Planck distances could exist. The question is: Are there any other limits that would come into play before that?
For example:
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How is light emitted by an incandescent lamp?
I am looking for better understanding of how light is produced in an incadescent lamp. More specifically: how is the kinetic energy of electrons converted to light?
Are we dealing with interband ...
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