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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.

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Albedo of water vs temperature

This question arose out of pure curiosity. Is there a relation between the temperature of water and its albedo? Would the albedo increase if I increased temperature? Say I measure albedo by directing ...
Vivaan Daga's user avatar
8 votes
5 answers
2k views

Does color temperature limit how much a laser of a given wavelength can heat a target?

The Sun has a peak wavelength of around 500 nm and an effective surface temperature of 5770 K, and sunlight cannot be focused to make something hotter than the Sun, because this would be heat flowing ...
causative's user avatar
  • 912
-4 votes
1 answer
64 views

As I read an article on this website that light cannot warp space time fabric [closed]

But actually we know that energy is equals to mass then light energy can act like mass and it can create a black hole made up of light . As per Einstein equation E=mc² then why there is no black hole ...
Arpit Jha's user avatar
0 votes
0 answers
19 views

Spectral bands of liquids and solids

I understand that instead of spectral lines, for solids and liquids spectral bands form, but why exactly do these bands form? I cannot see a reason why energy should be continuous now if photon ...
Quin Gardiner Bax's user avatar
6 votes
7 answers
3k views

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 ...
Madeira Darling's user avatar
0 votes
0 answers
26 views

Solarization Spectrum

I'm looking to better understand the relation between the spectrum of the light which induces solarization in glass and the spectrum of the induced absorption. More specifically, I'm interested in ...
Yuval Weissler's user avatar
0 votes
0 answers
74 views

Is there a reason why in the astronomic pictures of galaxies and nebulosas there is so little green color?

From a quantum physics standpoint, why do astronomical images of galaxies and nebulae exhibit so little green color in their spectral composition? When we look at the pictures of galaxies provided by ...
Alfredo Maranca's user avatar
0 votes
1 answer
47 views

Directionality of laser light in vacuum [duplicate]

It is well-known that laser light is directional because of coherence from stimulated emission. This means that the light is emitted ONLY in the direction of propagation, and not in any type of ...
Prakash_S's user avatar
-4 votes
1 answer
56 views

The speed of a QM particle

In the original theory of quantum mechanics what is the speed of quantum particles, I am asking this because photons can only travel at the speed of light C. What about mass particles?
TheWhitelily2010's user avatar
0 votes
1 answer
23 views

Exit Pupil, Objective Aperture, Magnification, and Brightness

Why is it that for two pairs of binoculars, with equal aperture, the one with smaller magnification has larger exit pupil and results in brighter images? If I understand correctly, the aperture ...
guilhermemp's user avatar
2 votes
2 answers
102 views

Why do gaps in my blinds create multiple lines?

Multiple lines appear on my floor every morning from the gaps in my blinds. Why does this happen and does it have to do with light being a wave, like in the double slit experiment? If so could it be ...
user2918098's user avatar
2 votes
0 answers
56 views

Do we perceive colors through energy or photon counts?

For example, assume a light color red such that its frequency is half that of another light blue. If you were to have 1000 red photons incident on your eyes and 1000 blue photons, then the blue light ...
user2916292's user avatar
0 votes
0 answers
29 views

Can the rainbow illustrate the colors we can’t see? [duplicate]

Seen as how we’re only able to see a relatively small portion of the electromagnetic spectrum, does the rainbow “keep going” in the frequencies we cannot see? In other words; if we were able to see ...
Jonas Giske's user avatar
1 vote
0 answers
44 views

What is the range of noon sun color temperature, when a light meter reports full expected sunlight (+/- epsilon)?

My question came from trying to find what uncertainty bounds, if any, I can assign to a color temperature sensor, without access to an artifact with a precisely calibrated output spectrum. This leads ...
user3732008's user avatar
-4 votes
1 answer
86 views

Why does a ventilator appear to run leftwise and rightwise and back when spinning up?

My university professor, a friend of mine, asked me: "Do you know why, when a ventilator starts and during the process up to final speed, it runs clockwise and anticlockwise and back again to ...
George Kourtis's user avatar
2 votes
2 answers
134 views

Why can't we see green color in the sky? [duplicate]

From sunrise to sunset we can see a variety of colors in the sky. For example, during morning the most dominant color is blue whereas during sunset orange,red,yellow and there shades are more dominant....
Ishaan's user avatar
  • 517
5 votes
3 answers
2k views

Is it possible to get an electromagnetic wave equation if the speed of light were infinite?

In an old question: How would night sky look like if the speed of light was infinite? the best answer was voted down to negative credits. I cannot understand why. From Maxwell's equations, we derive ...
wiljo's user avatar
  • 59
1 vote
1 answer
87 views

What is light? how is it connected to electromagnetic radiation?

I am trying to understand how light works and electromagnetic radiation, from what I understand charges cause disturbances in electric fields, which triggers a magnetic field, and then the back and ...
Ranvir Choudhary's user avatar
2 votes
1 answer
82 views

How do we see the wave of light if we are not at the end of it? [duplicate]

Given that light is an electromagnetic wave why is it that I can see the ray of light without my eyes being in the path of the ray? For example in this image: The camera is at the side and looking at ...
Jack's user avatar
  • 31
0 votes
1 answer
62 views

Doubt regarding time lag during photoelectric effect

Recently,I was reading about the photoelectric effect and have a doubt regarding it: Suppose I irradiate a metal surface with a monochromatic beam of light of frequency 'μ' such that μ > μ0 where ...
Ishaan's user avatar
  • 517
1 vote
1 answer
39 views

Is it possible to see thermal columns?

The most common way gliders gain altitude is to circle in a thermal. Thermals are often found below cumulus clouds, or above dark areas on the ground. Without these signs, they are harder to find and ...
Yizhen Chen's user avatar
0 votes
1 answer
33 views

Color changes with polarization

Plane polarized light is passed through a second polarizer whose polarizing direction is, say, at $80^o$ to the polarizing direction of the first polarizer. How does one experimentally measure the ...
phil342's user avatar
  • 27
0 votes
1 answer
43 views

Does a mirror have an albedo of 0?

According to the Wikipedia definition of albedo, it measures the fraction of light that is diffusely reflected by a body. Let's consider the visible light wavelenghts; is a mirror an object with an ...
jack_O'Dim's user avatar
5 votes
1 answer
1k views

What mistake did Einstein make in 1911 when he miscalculated the light deviation?

When Einstein published the general relativity theory in 1911, why was the light deviation not predicted correctly? What was the incompleteness of the theory when he published it in 1911? When and how ...
iVenky's user avatar
  • 131
0 votes
2 answers
55 views

What exactly happens to a light ray that is incident on the vertex of 2 mirrors inclined at some angle

So the question I had was that if we have two mirrors as shown in the diagram, what exactly occurs to the light ray that is incident on the vertex of the mirror? If we would like to construct the ...
Saketh V's user avatar
1 vote
1 answer
51 views

Would we be able to see the superposition of two X-rays where the frequency of the modulation matches visible light?

Suppose I had the superposition of two electromagnetic waves whose angular frequency was in the X-ray region. Together they form a composite made of a carrier wave and a modulation wave where the ...
Hadi Khan's user avatar
  • 531
1 vote
0 answers
37 views

How to determine if an observer can see an object with multiple mirrors?

How do I determine if an observer can see an object with multiple mirrors? I came across this image online and I am wondering if the observer (point O) see the object (point A) My attempt: I tried ...
Astrovis's user avatar
  • 187
13 votes
5 answers
7k views

How do photons have temperature?

On the internet, I found "Temperature is a measure of the average kinetic energy of the particles in an object." (source) So, this temperature should be a result of friction. Light is also ...
Shristeerupa's user avatar
0 votes
0 answers
23 views

Blue color scattering [duplicate]

I'm trying to understand, in terms of cross sections, why is the sky blue? Intuitively, blue has a smaller wavelength than the rest of the colors so it can "see" the internal structure of ...
MTYS's user avatar
  • 369
2 votes
4 answers
338 views

Why electrons do not emit electromagnetic radiation when they "jump" to an excited state?

According to electromagnetism, accelerating charges emit electromagnetic (EM) radiation. However, according to quantum mechanics, electrons do not emit EM radiation while they "orbit" around ...
MrDoppler's user avatar
3 votes
4 answers
328 views

A question about circularly polarized light

At work, a senior colleague thinks that circularly polarized light does not exist. My problem is that we both work on a project involving polarized light. In some occasions, I would like to point out ...
Y bueh...'s user avatar
0 votes
1 answer
45 views

What is a convex-concave lens?

I came across this term while studying for optics, and I'm unsure as to what this means. My thinking is that it might be a meniscus lens, but the text separately give two different models for each ...
Astrovis's user avatar
  • 187
0 votes
1 answer
38 views

Pointing flash at LCD television creates a weird diffraction effect

I was looking around my room for something with my phone’s flash on, and noticed a very unique pattern reflecting off of the television. FYI. The flash is white. Any idea why it diffracts like that? ...
RedP's user avatar
  • 390
1 vote
0 answers
37 views

How to measure light intensity in a room?

Does anyone know how I would go about measuring the light intensity in a room? I'm not interested in knowing the lux reading, I would like to measure the $W/m^2$ due to thermal radiation in my ...
Cones's user avatar
  • 31
1 vote
4 answers
55 views

Question about relativistic mass and momentum transfer of Light

How can we reconcile the concept of inertia, typically associated with mass, with the behavior of light or electromagnetic waves, which lack classical mass but still exhibit resistance to changes in ...
Shantanu Binekar's user avatar
1 vote
2 answers
83 views

Light traveling long distances

I am a high school student and I always wonder if light is an EM wave, then how it can travel such large distances? I tried to search on the internet but the answers have solution of Maxwell's ...
Himanshu Nirwam's user avatar
0 votes
0 answers
30 views

I need to calculate the lateral displacement of light from a glass slab

I think I might have a solution to calculation the lateral displacement of light, however I'd like informed opinion on whether this is right. We first extend the incident line forwards. Now, we ...
Likhith Reddy's user avatar
2 votes
2 answers
75 views

If a weak light source is attached to a string, and someone swing this light source in circle. It seems that this light source is brighter. Yes or no

It may be truly a question of life and death. You know those glow sticks. As a sailor it is a good idea to carry one on our lifevest. Falling into the sea, those glow stick make a light source that ...
Pierre magnard's user avatar
1 vote
0 answers
36 views

Why does scanning a barcode off a mobile phone screen work?

I recently went to a store and showed the loyalty card on a picture taken on my phone. As the cashier moved to scan the barcode, I figured that this won't work. Laser light is presumably coming out of ...
Kotlopou's user avatar
  • 381
0 votes
0 answers
64 views

From a QED perspective, how is light created and propagated?

Using QED, what happens, exactly, when light is created? Let's say an electron loses energy by dropping to a lower orbital, causing quantum of energy to be "emitted." What is that energy ...
RickNZ's user avatar
  • 109
0 votes
0 answers
23 views

Can the physics behind AR glasses be entirely modeled by geometric optics?

If I wanted to get the image of a small LED screen to be reflected onto the lens of a pair of glasses, would an understanding of geometric optics be sufficient to model this scenario? I ask this ...
MXVG's user avatar
  • 1
0 votes
1 answer
32 views

What do the $x$ and $y$ axes mean on a chromaticity diagram?

I understand that the chromaticity diagram is a plot of visible wavelength colors. Since the visible wavelengths form a curve on the graph, what do the $x$ and $y$ axes mean? My thinking could be ...
Astrovis's user avatar
  • 187
0 votes
1 answer
48 views

General questions on the "big picture" of scalar diffraction theory

When studying diffraction, my courses at university stopped with frauenhofer diffraction, which - as far as I understand it - describes the diffracted far field for diffraction of a more or less ...
Pidrittel's user avatar
1 vote
1 answer
57 views

What will be the color of red laser pointer spot on green surface?

I have read this discussion enter link description here , yet I want to make things more clear. In ideal conditions is it true that red laser pointer spot will appear on white sutrface as red while on ...
Igor's user avatar
  • 73
1 vote
1 answer
57 views

Absorption spectra in films chemicals & dyes

For a science competition, we have to understand absorption spectra in films chemicals & dyes. But what is that? I've found resources on the absorption spectra of chlorophyll, but I'm unclear as ...
Astrovis's user avatar
  • 187
-3 votes
1 answer
110 views

Does quantum tunnelling have anything to with perception of light?

There have been studies suggesting that the sense of smell has something to do with quantum tunnelling but I'm afraid I don't know the exact details. Do we possess internal mechanisms that simply &...
DanielFBest's user avatar
1 vote
1 answer
32 views

Absorption and emission spectrum

I was wondering how do you see a spectrum when light is passed through a substance. Like most of the substances we use are opaque, so how does light pass through them without being reflected? Also ...
Hao Zi's user avatar
  • 11
0 votes
2 answers
60 views

How to propagate the wavefunction of a photon in single slit diffraction?

During my undergrad, I remember writing a simulation in which the diffraction patterns which emerge from light passing through a single slit were calculated. This was done, basically, by calculating ...
Gregor Hartl Watters's user avatar
1 vote
1 answer
55 views

Why does the energy (and thus frequency) of a photon entering glass stay constant if some is used up to accelerate electrons and slow down the light?

I'm learning optics and have been told that when light enters a medium (e.g. glass) and slows down the frequency of the light stays constant while it is the wavelength which is reduced. The ...
Hadi Khan's user avatar
  • 531
-1 votes
2 answers
62 views

Why is a bigger camera sensor better at low light than a smaller one?

People say a bigger camera sensor is better for light performance as the photo sensors are bigger and hence let in more light. But couldn't you just let the same light in and focus it down onto the ...
George kirby's user avatar

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