Questions tagged [visible-light]
Questions related to the perception and measurement of light (primarily in the visible range), its mathematical description, the reproduction of colors by different means, color combinations, etc. Please use the tag [electromagnetic-radiation] if you want to refer to the general form of light.
99 questions from the last 365 days
0
votes
1
answer
46
views
Why can't we see blue gas moving in the sky? (instead, we see uniform and stable color)
We all know that the sky is blue due to Rayleigh scattering. And also we know that the smoke from a cigarette looks blue(ish) due to this phenomenon. So, why do we see "uniform" and "...
2
votes
1
answer
181
views
What does a rainbow look like in Saturn due to the rain of diamonds?
Research tells that there could be diamond hail rain in Saturn due to black cloud of soot. So is there any possibility that you could see a rainbow from there? Well, the black cloud of soot and ...
-1
votes
3
answers
170
views
Is it possible to explain how electromagnetic waves propagate through a vacuum solely using classical physics? [closed]
I'm struggling to understand how electromagnetic waves are able to sustain through a vacuum without thinking of them as photons instead of waves.
Am I right in thinking of the situation as the wave ...
- 181
1
vote
1
answer
70
views
How does light in the observable universe behave for an observer falling into a black hole?
Everything is relative as Einstein has long ago discovered. The effects of relativity are especially apparent near the extreme spacetime curvature sources like black holes. For an outer observer, ...
- 11
2
votes
2
answers
106
views
How is this kind of rainbow formed?
Earlier, I saw this rainbow out of my window:
Sorry for the meagre quality. As you can see, there is a primary rainbow, but directly attached below the primary rainbow, another, fainter and thinner ...
- 121
1
vote
1
answer
56
views
Shadow from Direct Sunlight Visibly Brighter When Viewed Through Polzarized Lens?
I searched this site for about 10-20 minutes using both Google and its built-in search. Wasn't able to find any question similar to this one.
I've taken Physics 1+2 and an introduction to modern ...
- 11
3
votes
3
answers
575
views
Quantum vs classical behavior of monochromatic light
A polarized beam of monochromatic light in classical physics is described by something like
$$E = \hat z \cos(kx-\omega t),\quad B =\hat z\times E.$$
What happens if we aim this beam to a highly ...
- 1,685
8
votes
3
answers
939
views
Why don't objects 'invert' when viewed through a very small aperture? [duplicate]
We have seen in textbooks that, in a pinhole camera, light rays intersect at the aperture and then 'invert' inside the camera. But when I tried to replicate this by viewing objects through tiny holes ...
1
vote
2
answers
249
views
Why doesn't light have decoherence?
I was thinking that, if one were to make a realistic physics engine, quantum effects could be ignored due to decoherence making them insignificant in the result. However, for light, it seems quantum ...
- 571
0
votes
2
answers
151
views
Can I use a flashing light to map Earth's gravitational field strength or perhaps a large star's?
If a light on a satellite flashes above me at a steady pace and I move in a gravitational field below it I can tell that gravity is stronger where I am because the satellites light flashes more ...
user538613
1
vote
2
answers
700
views
How does light, specifically in the Twin Paradox, behave?
I am a highschooler currently doing personal research on astrophysics and the general and special theory of relativity. I have been told over and over again that light cannot go faster than $c$ from ...
- 19
1
vote
1
answer
149
views
Dispersion: Denser to rarer medium
We have studied dispersion of a ray of white light when it goes from denser to rare medium (from air to glass). But when the ray of light comes out on the other side, do the various light rays get ...
- 127
0
votes
1
answer
171
views
Why are electric 'sparks' bright?
My understanding of sparks are that they're produced by discharge of electric charge due to accumulation of a large number of electrons in a region and due to a high potential difference compared to ...
- 39
1
vote
2
answers
110
views
About reflection and transparent glass
Light rays incident and reflected back from the object to our eyes then only we can see the objects but in case of transparent glass the rays are not reflected back then how can we see the transparent ...
- 41
3
votes
1
answer
242
views
Why doesn't Rayleigh scattered light amplify intensity?
Let's consider some linear ideal infinite medium where infinite plane monochromatic wave is propagating.
Fluctuations of density cause relative permitivity to fluctuate and proportionally create ...
- 240
2
votes
2
answers
199
views
Can light emit all wavelengths, or only allowed energy levels?
Galaxies moving away emit redshifted light. If the speed of the moving away increases linearly, does the wavelength of the light also increase linearly, or discretely?
- 21
16
votes
6
answers
4k
views
Why doesn't a pinhole camera work with a large hole?
All the explanations in the internet about pinhole cameras show two rays from outside passing through a small hole and produce an inverted image inside. Why doesn't it work with a big hole? Or ...
- 271
0
votes
2
answers
192
views
Do mirrors create more light?
If I light a candle, I have x amount of light.
If a mirror reflects the flame, do I now have 2x the amount of light? If I add another mirror, does it triple?
And if I place 2 mirrors across from each ...
4
votes
1
answer
286
views
Will the linewidth (spectral width) of light increase when it passes through a transparent medium?
My question concerns a case where light travels through a transparent linear medium, where it slows down like glass. The classic explanation for this is the Ewald-Oseen Extinction Theorem.
Ewald-Oseen ...
- 109
0
votes
1
answer
242
views
Is there a relationship between Fermat's principle and radius of a black hole?
This question obviously could have been improved in many ways, and I'd appreciate if you answer it and pinpoint some holes/inconsistencies.
Assume that there is a black hole (or just a very very ...
- 117
4
votes
3
answers
996
views
Can light create sound?
High-schooler alert, be patient.
If we consider a Bohr Model of an atom used for introduction to atomic physics with a nucleus in the centre and electrons "flying" around it (no waves), then ...
- 117
10
votes
2
answers
2k
views
Sun turns blue when seen through a crossed polariser/analyser
It was sunset, and we were looking at the sun through our polariser/analyser setup. When the angle between P and A was zero, the sunset looked normal (albeit with an expected reduction in brightness).
...
- 13.5k
0
votes
0
answers
41
views
Why do speed of different colours of light vary in glass but are the same in vacuum? [duplicate]
Light is an electromagnetic wave and therefore it follows the wave equation.
$\frac{\partial^2 \psi}{\partial t^2}= v^2 \frac{\partial^2 \psi}{\partial x^2}$
Now with some maths, the wave equation can ...
- 384
-2
votes
2
answers
162
views
Is there a change in the light beam coming from an object that allows us to view it?
When light hits objects it is scattered and those light beams that hit our eyes make us see the objects.
But how does this allow us to see the objects?
Does that mean that the light beam going towards ...
- 189
1
vote
0
answers
79
views
Ray Optics— Number of Images proofs
I realise that formulae like n=360°/theta (-1) is based on the lemma type that each sector of theta degrees, starting from the sector MOM' (sector between mirrors) corresponding to exactly 1 image, ...
- 99