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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2answers
28 views

Why does the ray bend only in one direction?

By snell's law , the refracted ray bend away or towards the normal according to refractive index of the medium. But it can be seen that the refracted ray bends to the right by an angle when a ray of ...
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4answers
166 views

What makes Sun's light travel as parallel beams towards earth?

Sun's light appear to travel as parallel beams towards earth $_1$. Sun produces electromagnetic radiations through pp chain and other reactions in Photosphere $_2$. I don't see whether these ...
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0answers
34 views

Can we convert light to another spectrum?

Could we convert light from one spectrum to another just like how it does in a radium, using some device? If we could do that to a specific part of the emitted light, probably we could make 3-D ...
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1answer
55 views

Why can't we produce visible light from a radio transmitter? [duplicate]

Producing visible light from a radio wave transmitter: why is it not possible? If it is, what are the limitations?
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3answers
86 views

Relation between wavelength and system size

We always say that when a given light wave interacts with atoms bound in a molecule, only waves with wavelength close to the inter-atomic-spacing are able to probe the system. In other context ...
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0answers
34 views

The ratings for light bulbs [on hold]

I have been asked at my job what the ratings are for a light bulb (car beams) 3000-14000k? Can someone find out more about this as the packages don't have any source of info about these ratings. ...
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2answers
38 views

Light wave crossing media and the relationship between speed, wavelength, and frequency

There are many threads on this topic (like this one) but one aspect about the equation $ v = \lambda\nu $ still confuses me. I have read that frequency does not change when light crosses into ...
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0answers
35 views

Where does light go when you switch it off? [duplicate]

I have a lamp. When I switch it on, it immediately illuminates the surroundings. When I switch it off, the light goes away in an instant. Why is this? Where do the light particles go? Do they quickly ...
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2answers
42 views

Is there a material that could “convert” near infrared frequency to infrared?

I have a laser with a wavelength of 650 nm (visible red light) and was wondering if there is some sort of material that could be used to absorb and disperse a different frequency of light around (900 ...
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0answers
15 views

Filtering UV Light to Visible Light [closed]

I'm wondering if it is physically possible to filter UV light from 400nm to 100nm so that UV light is in the visible range. If we had a UV screen over a visible range screen, could there be two ...
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3answers
49 views

Does polarization remove any of the fields completely?

A light is made up of electric and magnetic fields oriented perpendicular to each other. Can polarization lead to the removal of any of the fields completely?
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1answer
98 views

Light in a box with positron walls instead of electrons

I understand that with a hollow cube with the inner walls covered in mirrors given a light source briefly, the light would eventually be absorbed. This is due to electron excitation I believe. So ...
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1answer
49 views

Non-polarised light

We know the beam of light oscillates in electric field and magnetic field, both perpendicular to both the wave of propagation and each other. What does, however, a non-polarised beam of light look ...
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4answers
46 views

How can a 360 Degree Rainbow be formed? [duplicate]

Just a while ago while I was reading news paper, I saw an amazing article. Someone had caught a photo of a 360 Degree Rainbow. But how is it possible. I mean after refraction the only rainbows that ...
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2answers
67 views

Is light emitted in zitterbewegung? [duplicate]

Recently I heard of Zitterbewegung, a trembling motion of the electrons in atoms that arises from Dirac's equation. I know that, according to Bohr's model, light is emitted when the electron "jumps" ...
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2answers
75 views

What does amplitude in wavelength of light physically mean?What oscilates with time in photon?

Like amplitude in wavelength of water waves signify the displacement of water particles about their mean position.
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3answers
3k views

How does light speed up after coming out of a glass slab?

As I learned today in School, my teacher told me that when light enters a Glass Slab it slows down due to the change in density and it speeds up as it goes out of the Glass Slab. This causes a lateral ...
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1answer
31 views

How do I calculate the apparent brightness of a mirror reflecting the sun at a given distance?

I've stumbled around trying to figure this out, but it just isn't my area and I haven't gotten far. This is for writing about an idea of a field of mirrors on the moon, on the terminator when the moon ...
2
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1answer
51 views

Does irregular reflection form images?

In one of my test papers at school, we had a true-false question which said "Irregular reflection can form an image." I marked it true, however I was not given any marks for the question. I asked my ...
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1answer
39 views

Radiance increase via two sources [closed]

Can two sources of white light shined at the same general location increase the resulting rasiance?
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1answer
16 views

Dynamic equations for propagation of light through dust

For smoothly inhomogeneous media light propagation can be modeled by Maxwell's equations with non-constant $\varepsilon$ and $\mu$. This allows to relatively easily model propagation in the medium ...
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1answer
44 views

Physical effects on light from stars

I was thinking about how we see stars at a distance, the light that travels from them is affected by the Earths atmosphere, gravitational lensing and dust etc., but there doesn't appear any equation ...
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1answer
41 views

Can we get a true negative of an image reversing the spectrum?

In photography the negative means the lightest areas of the photographed subject appear darkest and the darkest areas appear lightest. But I was wondering: is this the way how negative should ...
3
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1answer
53 views

Bending light (photons) into an orbit

I was wondering and researching about light bending and reflection - I'm wondering if its possible to bend a light beam into a loop (orbit)? I know that light can be bent and reflected (even 100% ...
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9answers
4k views

How would night sky look like if the speed of light was infinite?

Would it be brighter? Different color? Gravitational lensing? Would black holes exist?
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4answers
109 views

Space orientation of light waves

Recently I've started to be really intrigued with the electromagnetic spectrum and bumped into this problem: According to the wave theory of light (or any electromagnetic wave, really), the magnetic ...
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2answers
52 views

Attributes of a polarized light

Which of the following is true for a polarized light? The electric vector is constant in its module and direction The electric vector oscillates in every plane that passes through the ...
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10answers
412 views

How far can light go?

When a ray of light is projected, (say) from the surface of Earth to outside in space. The condition is that, there is no obstruction to it till infinity (it travels only in vaccum). My question is ...
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2answers
29 views

Plane polarized light?

I have heard about plane polarized light: light wave which has vibration in one plane. My curiosity forces me to ask a doubt, is there any way to produce polarized light wave which has vibrations in ...
2
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0answers
25 views

What property of medium is directly related to light propagation speed in that medium? [duplicate]

Refractive index is used to calculate phase velocity of light in medium, other than vacuum. Recently I had a discussion with somebody claiming that light is slower due to magnetic field of atoms. I ...
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2answers
54 views

Is there a relation between music chords and visible light palette [closed]

Ok I have no idea if this is the right stackexchange so if you know who would know please tell me :) In music there are groups of notes that, when played togheter, are basis to harmony. Since both ...
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0answers
32 views

Diffraction of a thin mirror

I have a question about a particular case of light diffraction. A laser light collides into a "hairline" mirror (I mean a straight line mirror that halves the wavelength dimension), see the image ...
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4answers
28 views

Is there some difference between blue light and light covered by blue paper?

Let´s talking only about photons absorbed by detector. Would it detect something else if the photons came from blue star than if the photons were filtered by blue paper? And what about ultraviolet ...
3
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1answer
29 views

Why does the light reflecting off of ocean water sometimes appear 'smoother'?

Looking out the window at some water in the Harbour - I noticed that some parts of the water appear 'smoother' than others. My question is: Why does the light reflecting off of ocean water ...
1
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2answers
59 views

Penny dropped in the water: What would you see if transmitted light is parallel to the incident surface

I'm working on a problem which asks what is the greatest diameter of a paper you can use to totally shield a penny dropped in the water from view. The question claims that if the transmitted ...
0
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0answers
40 views

Why can't we see Rainbows from its end points? [duplicate]

We see Rainbows many times, but we always see them Horizontally or from Sideways. Why can't we see it from under it?/From the point where it starts or ends(end points)? I also want to stress on that, ...
3
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1answer
58 views

Can unpolarized light be created from polarized light?

I have a question regarding this topic. According Stokes Parameters theory, unpolarized light could be described as a superposition of two independent beams of equal intensity and orthogonal ...
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0answers
23 views

Does dispersion take place in our eyes? [duplicate]

What do we see if a single ray of white light falls in to our eyes ? Doesn't it undergo dispersion ?
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1answer
38 views

Is it possible to project black light? [duplicate]

A thought passed by me and I wondered if projecting black light was possible. We can make lights with many other colors, but I'm not so sure about black. So, is it possible? Has it been done?
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4answers
42 views

Why is microwave better than visible light for point to point data communication?

In the electromagnetic spectrum, it appears that the shorter the wave length, the better the bandwidth due to higher frequency. Some communication systems utilize microwave to transmit data to offer ...
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0answers
52 views

Effect of varying distance of light source from a Light Dependant Resistor

I'm doing the experiment described here and I have a few questions regarding it. I've taken a mini-LDR hooked to a multimeter set to $\Omega $ and a $25\,\mathrm W$ Light Bulb to plot the following ...
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2answers
29 views

Why doesn't the color of an object change when signal of different frequency impinge upon it?

Correct me if I'm wrong but I've always thought that the color that an object has is due to the oscillation of the atoms that makes up the material of that object. When white light is shine upon an ...
29
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3answers
2k views

What do we see while watching light? Waves or particles?

I'm trying to understand quantum physics. I'm pretty familiar with it but I can't decide what counts as observing to cause particle behave (at least when it's about lights). So the question is what do ...
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4answers
151 views

Why Light isn't like an Acoustic wave?

I just wanted to know why light isn't an Acoustic wave.Is it because light wave doesn't obey acoustic properties?
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2answers
61 views

Black Holes and Light [duplicate]

It is said that photons have zero rest mass so how can gravitational force of a black hole affect light? And if photons do have some effective mass while traveling at speed of light then only can a ...
2
votes
2answers
71 views

Why human and most of vertebrates cannot see Near-Infrared light (720nm-1500nm)? [closed]

On daytime, the surface of Earth is illuminated abundantly by light of spectrum from 250nm-1500nm, that includes near-ultraviolet spectrum (250nm-380nm), visible spectrum (380nm-720nm) and ...
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1answer
58 views

What is causing the separation of light in this image?

Reflection of keychain LED light on Macbook Pro (2014) screen I have also observed this phenomenon on my mobile phone and on a tablet. I assume this means it is somehow related to backlit ...
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3answers
85 views

Why can we see white objects as white under the sun if the sunlight is yellow?

I get that the sun is producing white light which is scattered threw our atmosphere so that the light of the sun reaching our eyes is yellow. So how come if I look to a piece of white paper under ...
1
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1answer
45 views

Defining photons

I've read every book for my course and all of them describe photons as wave-packets/"bursts" of the EM wave. I just can't appreciate this view of photons. From what I've gathered on photons: Photons ...
2
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1answer
29 views

Darkest matter on Earth (“pure black”)

What is (for a human's eyes) the natural or synthetical matter on Earth (i.e. not in Space) that emits the least quantity of visible photons while being lightened by sunlight? In this matter, how is ...