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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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Predicting the frequency of visible light [on hold]

Why can't the Standard Model predict the frequency of visible light? For example, were it possible to invent a universally extensive 'field' in which wave properties are inherent, including those of ...
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0answers
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unusual questions regarding controlling polarized light with LCD shutters

1) Is it correct to assume that if a light is already polarized one of the polarizers on the LCD shutter itself is not required to be present to selectively block it? 2) Is it correct to assume that ...
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2answers
35 views

Can an invisible neutron star exist? [duplicate]

Basically a neutron/quark star that approaches it's Schwarzschild radius but doesn't surpass it. Its gravitational force is great enough to not let light escape from it, but not great enough to become ...
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4answers
64 views

Can light radiation pressure change its own path

Well i have seen that light creates radiation pressure Can two light waves coming from two different direction change each others path?
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2answers
56 views

Will any charge oscillating in space create an EM wave?

Would it be correct to say that any charge oscillating in space (regardless of the spacial amplitude) at a given frequency will emit an EM wave of the same frequency? related: What change in an EM ...
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1answer
23 views

Why does certain clear plastic have an inner glow?

A type of plastic used in packaging for tamper resistant seals appears to have (what I can best describe as) a purplish inner glow under sunlight, and perhaps other bright light. In the image below, ...
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1answer
34 views

Does polarized light reflect in the same polarization?

If vertically polarized light hits a linear polarizer aligned at a 45 degree angle from the polarization of the light, my understanding is 50% of the light will pass through and have its polarization ...
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1answer
40 views

How does reflective Heads Up Display (HUD) film work?

I've been seeing this reflective HUD film more and more. It seems to let you look through it, but reflects the brighter parts of a display. The end result is similar to a video game where you get a ...
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1answer
37 views

How is the diffraction (or interference) pattern in this photo explained?

I noticed the above photo on a website (https://www.aapt.org/Programs/contests/pc09full.cfm?Meeting=SM09&Category=Natural&Placing=44). How the pattern can be explained bothers me for some time....
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Relation between critical angle between media different in optical density and their refractive indices?

The law states that: Sine the critical angle between two media = relative refractive index between 1st & 2nd media = absolute refractive index of 2nd medium/absolute refractive index of 1st medium ...
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1answer
34 views

Is frequency of Electromagnetic wave it's intrinsic property?

I was solving a simple refraction problem where the wavelength and velocity of the sodium light needed to be calculated after refracting through glass from air. Now after calculation I found the ...
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1answer
43 views

Does it give sense to speak about field distribution of a single photon?

A Point source of light has radial symmetry. If the source gets attenuated so that only a single photon is leaving each hour, can I still argue, that the field of the single photon is radial but the ...
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0answers
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When light hits my glasses, each lens shows different color

So I was holding my glasses in a certain angle, and the light source is directly above it. When looking through one lens, I see purple straight 'lines', and through the other lens the lines are teal....
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0answers
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Why do the fish appear to glow blue and orange? [on hold]

I was visiting an aquarium today, and the fish and the rocks had a visable blue glowing outline on every edge pointing in one direction, and an orange glow in the other direction. It was as if a child ...
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0answers
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While flying over Rome we noticed that during sunset, there was a green color between the red and blue of the sunset sky. What causes it?

The picture has only been trimmed and not edited. The green is visible when the red or orange tapers off into the blue. Is this different from what causes the green flash? We were flying from Rome.
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Is light a 3-dimensional wave?And how is that measured?

I'm assuming the answer to the first question is yes, if I'm wrong, this will be an easy one to clean up. Forgive me is this is a stupid question. When thinking of light waves or particles as waves, I ...
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0answers
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Creating light with combining $E$ and $H$ fields

We know that light is an electromagnetic wave. So if we take electric field $E$ and magnetic field $H$, combine them perpendicular to each other, and make them oscillate harmoniously, would it create ...
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Monochromatic light source through double slits, find the wavelength of the light source? [closed]

The question is "When a monochromatic light source shines through a double slit with a slit separation of 0.20 mm onto a screen 3.5 m away, the first dark band in the pattern appears 9.1 mm from ...
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1answer
193 views

To what extent is the heat in the focal point due to visible light?

When focusing sunlight on a piece of paper, e.g. with magnifying glass, the paper will be charred and might eventually even burn (assuming low cloudiness). To what extent is the heat a result of the ...
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1answer
31 views

Reflection in a lake

Suppose there is lake. And a cloud is at a height h above it. The reflection of the cloud will be at the same depth in the lake as the height of the cloud or at the surface of the lake or at the base ...
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0answers
42 views

Difference between color and effective temperature

What is the difference between color temperature and effective temperature of a star? I have gone through the pages at wikipedia, but I still do not understand that. Can anyone please help?
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2answers
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What happens if separation between slits is greater than separation between slits and screen in YDSE experiment?

I was studying Young's double slit experiment (YDSE) in which it was derived that the formula for path difference ($\delta x$) is : $$\delta x = \frac{y \cdot d}{D}$$ Where $y$ is the vertical ...
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0answers
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Can light concentrated through convex lens be “cooled down?”

I've just been assigned this biology design project where I'm being tasked to create a device for maximizing "sunlight exposure" of crops and am unsure of this particular question, for the design of ...
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Why we can't effect the direction of electric field through lens/mirror since we can do it for light? [closed]

Presence of light in path of light wave changes the path. But for electric field from static charge do not why?
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3answers
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What change in an EM field is required to create an EM wave?

From here To generate a long wavelength requires an aerial of roughly one wavelength in size. and here One of the difficulties posed when broadcasting in the ELF frequency range is antenna ...
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2answers
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How does scattering of light happen in atmosphere?

I know that the scattering of light decreases as inversely proportional to the 4th power of wavelength. But what happens at the atomic level? Does the photon get absorbed and re-emitted? Does the ...
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13answers
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If visible light has more energy than microwaves, why isn't visible light dangerous?

Light waves are a type of electromagnetic wave and they fall between 400-700 nm long. Microwaves are less energetic but seem to be more dangerous than visible light. Is visible light dangerous at all ...
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2answers
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Gravitational Lensing: Up, Down or Sideways

I have been reading about Eddington and his measurement of 1.75 arc seconds in 1919. What I am wondering is why was the measurement lateral? I picture a beam of star light entering a curvature of ...
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1answer
60 views

Why do cones require more light than rods?

The title says it. In our eyes, why do cones require more light than rods? Like is it because of the energy needed to change the state of the existing atoms, the molecules or what leads to the need of ...
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5answers
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If perfect blackness violates the Uncertainty Principle, how isn't dark matter a violation?

In a recent tweet, Dr. Michio Kaku stated that perfect blackness would violate the Heisenberg Uncertainty Principle, i.e. every object must emit some radiation. I have two questions regarding this ...
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0answers
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Superradiant scattering in ergosphere?

In a black hole there is a region of space where only energy can escape, the ergosphere. I read superradiant scattering can allow lights to gain energy much like gravity assist, what is the different ...
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0answers
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Using a Signal Generator to Pulse a Laser [closed]

When I use a signal generator to pulse a laser it works great up to about 35khz. Beyond that the response from the photo diode degrades quickly. The signal generator when connected directly to the ...
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2answers
49 views

What is the max amount of photons per second of the rods and cones in our eyes?

The title says it all. I just cannot find any information about this - I have tried for so long now. Therefore, I figured that I could reach out to some clever guys in this forum for help instead:) ...
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Feynman’s Treatment of an Opaque Wall

First time poster. I’ve been reading Feynman’s Lectures on Physics, and I’ve just finished reading his treatment on diffraction. Feynman described a method of thinking about an opaque wall that was ...
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1answer
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Missing link re: how does kelvin relate to temperature when talking about color temperature?

I am an electrician at a commercial electrical company. There is an in-house training program that posits the datum that when talking about the designations of color temperature for lights (for ...
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0answers
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Do red lasers shoot longer than green ones?

I am aware of the fact that our eyes are most sensible to green color and therefore green lasers seem stronger than other colors when being scattered through the air. However, since red wavelength are ...
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2answers
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Photons, light and electricity

Light is ultimately composed of photons. Photons are also force carriers of the electrical force. When an electric motor is turning it is photons which are turning it. What is the relation between ...
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1answer
85 views

Does light know the future? [duplicate]

As I understand it, if light is traveling at the speed of light, then from it's point of view space is fully compressed in its direction of travel. Does that mean that from it's point of view, light ...
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3answers
91 views

Does light get acceleration due to gravity? [duplicate]

When an object, say a ball, is attracted by the black hole it gets acceleration due to gravity. Suppose light is moving towards the black hole vertical to it... then does it gain acceleration due to ...
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1answer
63 views

Energy spacetime warping

If energy warps spacetime, then does light warp spacetime? And if special relativity says that things near the speed of light increase in relativistic mass, then does light have a relativistic mass? ...
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0answers
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How does brightness affect color? [duplicate]

How does brightness affect the color of light? For instance, the sun might be yellow because of the blue scattering when the light travels through the atmosphere - but if you look at it, it seems ...
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2answers
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How much light is needed to quality as possible dark matter candidate?

I know when scientists study dark matter they have already excluded light because of it's negligible effect on the galaxy and of course we are able to observe it directly, I am curious just how much ...
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2answers
107 views

Why does the sun always have some whiteness? [duplicate]

So the atmosphere scatters light on its way to earth, making the color of our sky. For example, when the sky is blue on a clear, sunny day, the sunlight appears somewhat yellow because the blue light ...
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1answer
45 views

Do binary black holes mergers emit light?

I am not referring to Hawking radiation and although I see there should be no way the collision can produce electromagnetic wave after all, a black hole is simply a region of space right?
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0answers
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If there is no destination does light actually get emitted? [closed]

If the action of least principle says light needs a destination what happens when we shine a laser into the dark region of the microwave background radiation? Alternatively, if we put a light source ...
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3answers
2k views

Can visible light be affected by magnetism?

I would like to start by saying that I am not a physicist and I don't really know a lot about the subject! We all know that without Earth's magnetic field, electromagnetic radiation from the sun ...
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0answers
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Rayleigh scattering from smaller wavelengths

I've read that UV light cannot "penetrate" the atmosphere as easily during winter. But what does this exactly mean? My hypothesis is that due to rayleigh scattering, since light with smaller wave ...
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3answers
67 views

What is the purpose of glass in mirror as it only reflect very little light?

In a typical mirror there is a thick layer of glass followed by a thin layer of silver coated on one side of the mirror which reflects most of the light, what purpose do the glass have?
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1answer
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What are the “real” primary colors and complementary color pairs?

If CMY are the true primary colors of subtractive color theory, are the complementary pairs yellow and blue, cyan and red, and magenta and green the "true" opposite color pairs? For example, a makeup ...
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1answer
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Minimum angle of deviation - Thin prism

I have two questions here. The first is why can we get the minimum angle of deviation of a trianglar glass prism when only the angle of incidence equals the angle of emergence. It seems it's a maths-...