# Tag Info

## New answers tagged wavelength

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 (...

### 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 ...
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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 ...
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### 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 ...
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### 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.

### 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 ...
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### 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 ...
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### 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.
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 ...
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### 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 ...
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### 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 ...
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