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.

learn more… | top users | synonyms (2)

0
votes
2answers
57 views

Light wave particle duality

I have studied about the dual nature of light and all the experiments that proved light was a wave and sometimes a particle, and I am comfortable with the concept that it can be both. However, I have ...
0
votes
0answers
30 views

Does nature of light depends on its Time of Interaction?

I was trying to understand how to "feel" about light. I have formed a notion which I couldn't find anywhere. So please tell if I am correct. Also please give theoretical explanations if possible (and ...
1
vote
1answer
57 views

Calculating the color temperature and intensity of skylight with an algorithm

I think it will be possible to calculate the natural sky light intensity and color balance (CCT) based on time of day/year, GPS location. Has anyone seen a formula/algorithm for this? I would like to ...
0
votes
0answers
45 views

Index of refraction for travelling EM wave problem

Let $n_1$ be the index of refraction of the first medium and $n_2$ be the index of the second medium. When $n_2>n_1$, then for an incident angle of $90^{\circ}$ we get a refracted light at a ...
3
votes
1answer
170 views

Refraction: Energy flow, tunneling and Evanescent EM waves

In the full internal reflection case where we have a refracted evanescent wave, If another object is nearby, then we could have wave tunneling phenomenon(frustrated total internal reflection). I am ...
0
votes
2answers
59 views

Confusion in difraction experiments

I had a confusion in the diffraction experiment about which I was taught in school. According to the formula we Derived The width of the central maxima decreases on decreasing width of slit and vice ...
0
votes
2answers
39 views

Photons reflecting off matter

When photons reflect off matter, do they always lose momentum to the object? If they lose momentum to the object, that means they lose energy, and so their frequency should decrease. However, when we ...
0
votes
1answer
61 views

light effects of electric current

In german high school textbooks and curriculua, the distinction of following main sorts of effects of electric current is usual: magnetic, heat, light and chemical. My question is, whether the glow ...
7
votes
2answers
1k views

How can a slowed light ray bend?

If light is traveling through air, it slows down and ends up bending. But how? If I'm running straight, and I get slowed down, shouldn't I still be running straight?
6
votes
2answers
158 views

Why can we see the earth from outer space if the sky is blue?

As far as I know, the sky is blue because as light from the sun enters the atmosphere composed primarily of wavelengths of visible light. However, as the light happens across molecules of oxygen and ...
0
votes
1answer
33 views

Is an iPad screen an Optical Prism?

One day, I noticed that sometimes, when there is an iPad right below a light, such as a chandelier, when viewed from an angle, one can see what looks like a spectra of colors. Is the iPad screen ...
0
votes
2answers
75 views

Humans and color at night [closed]

Why we can't see colors at night?
1
vote
1answer
70 views

Why do 3d movies have a red and blue “double image”? [closed]

My question is why do 3d movies have a red and blue"double image" that is basically just a few inches to the right and left of the real image. And how does this help us see the image as "3d". Does it ...
0
votes
1answer
46 views

How can a material be conductive and transparent at the same time?

Transparent conducting films for example. On one hand, the band structure of transparent materials must have a large enough HOMO-LUMO separation. On the other hand, conducting (metallic) materials ...
0
votes
0answers
15 views

Can measuring the refraction index in an object measure the strength of the quantum gravity between atoms of the object? [duplicate]

Is measuring the refraction index of an object a way of measuring the strength of the gravitational force between the atoms of the object (measuring quantum gravity)? From reading Snell's law of ...
0
votes
0answers
30 views

What is the pure form of energy? [duplicate]

What is the pure form of energy? Einstein in his energy mass equation derivation said that electromagnetic radiation is pure form of energy.
0
votes
1answer
36 views

How long will the light exist inside the sphere?

Ok, so let's say we have a very thick, but hollow, metal sphere. The inside of the sphere has a radius of 100 meters. The sphere also has a door that can be opened and closed and when closed makes an ...
0
votes
2answers
68 views

Photoelectric effect and energy of light

I have a doubt about photoelectric effect and the nature of light in general. From what I understood, in order to ionize a piece of some material, I need an electromagnetic wave with a frequence ...
0
votes
1answer
68 views

Can more than one photon be in the same space as another photon?

I have heard light described as a particle that travels in a wave. I have heard that waves are unique in that two waves can take up the same space as they are travelling, either through constructive ...
1
vote
1answer
37 views

Why is blue darker than yellow in an analog black and white photograph?

Blue is perceived darker than yellow by the human eye, because of biological principles within the eye. I can understand that therefore, when making a picture black&white in software like Adobe ...
0
votes
1answer
19 views

Which coefficients are needed to numerically obtain transmission spectrum?

I'm using Omnisim program. I would like to obtain transmission spectrum of certain material so I have created two polynomials: one representing real refraction coefficient and one representing ...
2
votes
2answers
84 views

Why can I always see a star? [duplicate]

Light moves along straight lines... Got it. So if the light from that faraway star is traveling in a straight line, and that beam is, considering the distaces involved, at best one or two photons ...
0
votes
1answer
39 views

Ultraviolet light in dark environments

I was looking into night vision equipment recently and found that some work with ultraviolet light. How much ultraviolet light is around at night? Is there enough ultraviolet light to see in the dark, ...
3
votes
2answers
255 views

Will high amplitude, low frequency light be capable of wrapping around a macroscopic object? [duplicate]

To me, as a macroscopic observer of light, it appears that light moves in straight lines. If I shine a light at object A and object B moves between me and object A, the light hits, i.e. gets blocked ...
1
vote
2answers
186 views

Can matter have 100% reflection?

Is it possible to have matter that reflects all the light and does not absorb light at all? If thats possible then we can store light inside it right? I think we can trap light inside that matter in ...
0
votes
0answers
35 views

Speed of Light with trains [duplicate]

Suppose that there is a train (train1) going at 100 km/h. The train is infinitely long. Suppose that there is an other train inside train1 (train2), which has a speed of 100 km/h also. So for a ...
0
votes
1answer
26 views

Finding the distance from the center of airy disc to first airy minimum?

This image is taken from the manual of photography, by Elizabeth Allen: How do I find it? The formula is supposed to tell me how to find this distance, but the formula requires R which depends on ...
1
vote
3answers
179 views

Can two 2500 K light bulbs replace one 5000 K bulb for growing plants indoors?

In an effort to assist an old Greek woman I find myself in need of greater minds. A 5000 Kelvin light bulb is required for her indoor fig plant. Can I get away with substituting two bulbs each in ...
2
votes
0answers
42 views

The properties of light photons [duplicate]

Please consider a closed room with light reflecting walls and in the centre of the room there is a Lighting Bulb. Now if I switch on the bulb, the room is obviously illuminated with light. When I ...
-1
votes
1answer
57 views

What exactly is light? [duplicate]

What is light in terms of physics? Whenever looking for definition on the internet getting explanation or translation of my language, a common definition/explanation for light was Light is light. ...
2
votes
2answers
76 views

Why doesn't dielectric materials have coloured reflections like conductors?

I'm a 3D artist trying to learn the basic (or perhaps even intermediate) level of physics of photorealistic rendering. But most artist and tutorials on the internet have little to no clue of the ...
0
votes
0answers
13 views

What is A2L refractive index polynomial?

I'm working with a photonic modelling software and in the manual I saw that I can specify refractive index of modelled material with following polynomial: ...
0
votes
1answer
84 views

Would a camera that only takes light at 90 degrees work?

From what I understand cameras and biological eyes work in a similar fashion, they all take light in a cone and distances are perceived as the angle which the object takes up rather than it's physical ...
0
votes
1answer
29 views

When light is reflected, if some of the light is absorbed in the particle, does it change the particle?

Which color/frequency of the light is absorbed and which part is reflected? How is it determined which part will be absorbed? Does that depend on the particle? N.B: When I say particle, please keep ...
-1
votes
1answer
33 views

What are diferent reflection percentages of different colors?

I don't need any accurate answer. Suppose reflection percentage for white is 100% (which is not even true for mirrors) then what will it be like for different colours like violet, green and red etc of ...
-1
votes
2answers
188 views

Light and vision (why we can't see without light) [closed]

I have heard that light comes from object and we are able to see the image of that object. But I can't understand why we can't see without light and how we are able to see object but not in dark. MY ...
1
vote
1answer
34 views

What are some of the empirical proofs of electromagnetic polarization? [closed]

I am aware of how polarization follows from Maxwell's equations, and how it is possible in transverse waves in general. I also know that Huygens, in his great Treatise on Light, first discovered and ...
-2
votes
1answer
77 views

If photons do not have mass, why does light get attracted such that it cannot escape a black hole? [duplicate]

Does gravitational force of black hole attract the light? Or is it something else?
3
votes
1answer
79 views

Why can't we see better with an antenna?

Or alternatively: Why don't antennas look like telescopes? If visible light and radio transmissions are the same thing, why is there such a difference in the equipment we use for augmenting it?
0
votes
0answers
16 views

Can waves change their roll axis?

If I roll a laser emitter 90 degrees on its roll axis, will the "up" and "down" motion of the laser-light wave also roll with orientation to the emitter so that to me it is now osculating "side" to ...
0
votes
1answer
94 views

Angle of minimum deviation

A prism of angle $60^\circ$ deviates a ray of light through $40^\circ$ for two angles of incidence which differ by $11^\circ$. What is the refractive index of the glass of the prism? If we are ...
-2
votes
1answer
81 views

burning candle flame disturbed by unseen force .What could this force be?

If a burning candle were placed in a enclosed glass box with a sufficient amount of oxygen to stay ignited, What outside source could interact with the flame causing a disturbance?
0
votes
1answer
25 views

Is there a limited light waves emission rate?

Is there? I mean, say, the sun emits light waves towards us and those waves travel through vacuum at the speed of light, or c. But does the sun emit those waves in ...
-2
votes
2answers
46 views

Will light continue traveling after the source has stopped producing light? [closed]

Will light continue traveling after the source has stopped producing light?
0
votes
1answer
31 views

How did Cavendish measure the deviation of light from the Sun?

On today's date in 1731 was born Henry Cavendish. He is mainly know for his Chemistry research, however, while I was reading his biography I've noticed that he also calculated the bending of light due ...
0
votes
2answers
63 views

Is it possible for two strong lenses to cancel each other effects?

Is it possible for a lens system for 2 strong lenses to cancel each other, so it looks almost the same as a common glass, while at the same time making an object in between them appear big and ...
0
votes
1answer
78 views

How can travelling at light speed affect light itself? [duplicate]

~Hypothetical Scenario: Your driving in a car (with the headlights on high beam) and you gradually get faster until you reach the speed of light. Raised Assumptions: You can see in and out of the ...
0
votes
0answers
31 views

Why can we treat (most) metals classically at room temperature?

When we consider how light and metals interact with each other at room temperature, the Drude model, which is a classical theory, is usually and successfully used. My lecturer explained something ...
0
votes
2answers
64 views

How does thin film interference work?

So thin film interference is when light is half-reflected half-refracted then the reflected and refracted wave interfere with each other to produce another color. What I don't understand is that the ...
1
vote
3answers
50 views

How does color (or reflection in general) work?

I'm confused, does the absorption and emission determine the color of something? Or does that only happen when something is emitting energy? When light hits an object, the photons get absorbed, then ...