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1 vote

Could the increasing anisotropy of the universe lead to an additional blueshift?

It seems to me that what you are pointing out is related to what is known as the (integrated) Sachs-Wolfe effect, which has been considered in the missions that have measured the CMB anisotropies (...
ouroboros's user avatar
0 votes

How does flute work?

I have not studied these flutes but from general physical principles I can see the following. First, we recall that a sound wave is a pressure wave, and at the same time a wave in the density of the ...
Andrew Steane's user avatar
1 vote

Does the energy of a photon in comoving space change?

The energy of the photon decreases as the reciprocal of the scale factor. Typically, this can be interpreted as the wavelength being "stretched" by the expansion, but alternatively you can ...
ProfRob's user avatar
  • 132k
0 votes

Why is the shorter the wavelength, the smaller the object you can image? and vice-versa?

Here is a simple mental picture which may help. Draw yourself a wave chain of sine waves going across the page. Now imagine inserting an object into the trough between two maxima in the curve. To get ...
niels nielsen's user avatar
-2 votes

Light waves can't have a wavelength

Panagopoulos, D. J. (2018). Man-made electromagnetic radiation is not quantized. Horizons in world physics, 296, 1-57.
Michael Luhr's user avatar
4 votes

Light waves can't have a wavelength

Something does not need to be sinusoidal in order to have a wavelength. It just needs to be periodic or repeat after a certain distance. More generally, if $\lambda$ is the smallest non-negative real ...
Jbag1212's user avatar
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2 votes

Light waves can't have a wavelength

Sahand gave a really great answer but I'd like to offer a different perspective. Edit: It was pointed out in the comments that energy conservation isn't enough to give periodic solutions. Which is ...
ShawnS's user avatar
  • 51
0 votes

Light waves can't have a wavelength

Time domain Maxwell's equation never implies periodicity. If time harmonic representation of Maxwell's equation is done than by default idea of periodicity automatically arise in equations.
Somen's user avatar
  • 1
36 votes
Accepted

Light waves can't have a wavelength

You're right in saying that you can't always attribute a unique wavelength to an electromagnetic field. However, it's a simple consequence of Fourier analysis that you can write any field as a ...
Sahand Tabatabaei's user avatar
2 votes

Minimum frequency for a dipole antenna to work

As already remarked in the comments, the optimal frequency is based on the "1/2 wavelength" rule. But to what extent do things get worse at lower frequencies? To make this more ...
Jos Bergervoet's user avatar
2 votes

Minimum frequency for a dipole antenna to work

No, but to maximize the radiated power at any frequency the dipole (horizontal, center-fed) must be 1/2 wavelength long. This means 5 meters at 30 megahertz, 50 meters at 3 megahertz, 500 meters at ...
niels nielsen's user avatar
-2 votes

How do wavelengths add-up?

Simply, the answer is: λ_resulting wavelength = (λ_color-1 + λ_color-2 + λ_color-n)/n So their mixed wavelength would be: 550nm = (650nm + 450nm + 550nm)/3 550nm would be the same wavelength as the ...
guest_friend's user avatar
0 votes

Question about fundamental frequencies

To add to John Hunter's correct answer, I'd like to add the justification for why harmonics behave so. It's entirely because of the constraints. Fixing the string at both ends means that the ...
Cort Ammon's user avatar
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