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20 views

Refracting an image through 2 prisms

my question might be quite simple for some of you but I don't have any idea what the result of such an experiment would be... If you would take an image emitting light such as a video from a screen ...
4
votes
2answers
74 views
+50

Why does gradually increasing refractive index coating reduce reflection?

Why does gradually increasing refractive index coating reduce reflection? EDIT: As @Michael Seifert nicely describes in his answer, reflection only occurs if there is an abrupt change in refractive ...
0
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2answers
109 views

Snell's law and Fermat's principle

I have read this sentence on a book about the Snell's law of refraction, referring on a ray that passes from air ($n_1=1$) to glass ($n_2=1.55$): "Snell's equation can be derived from Fermat's ...
-3
votes
1answer
63 views

Bending a Laser Beam [closed]

We can bend a Laser beam by varying the refraction coefficient of the air. We can bend a Laser beam by dispersing into the air small particles that have the same effect on the Laser Beam and small ...
1
vote
2answers
90 views

Why does violet light bend the most? [duplicate]

When white light passes through a prism, refraction occurs and it splits into its seven constituent colours. If the spectrum is obtained on a screen violet light appears much more bent than red light. ...
0
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2answers
35 views

Angles of Refraction,Internal reflection and incidence

First ill ask my question in brief and then ill elaborate it below... Theoretically is it that internal reflection occurs within a solid sphere(which is considered to be the denser medium) if and ...
0
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1answer
25 views

Calculated focus of an asymmetric bi-convex lens

So I've been working on modeling an optical system using ray tracing. I've finally gotten to the point where I am testing things however I've come across something I'm not entirely sure of. I'm ...
16
votes
4answers
2k views

Reverse of diffraction

Can we arrange a practical in such a way that the dark and bright bands in diffraction grating be allowed to pass through the same slit to get the original light (i.e the incident light before ...
2
votes
1answer
85 views

Do photons “bounce off” of electrons?

I’ve been reading a book, and in one part the author explains how electrons only absorb the wavelengths of light that can take them to an excited state, i.e. that can take the electrons to a higher ...
3
votes
1answer
52 views

Why does the intensity of the scattered light vary when a monochromatic laser is shined into a transparent object?

When a laser is shined into a glass ball such as this video (link) or a bottle of water (link) the light is refracted through the whole transparent body. However, the intensity of the light scattered ...
24
votes
3answers
4k views

Why doesn’t a normal window produce an apparent rainbow?

When light refracts in a prism it creates a rainbow. My question is, why don’t all windows or transparent objects create this dispersion, i.e. why is the refractive index dependent on frequency in a ...
2
votes
2answers
114 views

Why does a prism refract light into a rainbow? [duplicate]

Why does a prism refract light such that the different frequencies of light “spread out”? The same goes for rainbows, why do the raindrops “spread out” the different frequencies of light?
1
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1answer
52 views

Why light travels through shortest path during refraction?

I know in order to compensate with change in speed but how does Light actually know which path is less dense or more dense?
3
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4answers
82 views

Why does frequency remain unchanged in light refraction but wavelength doesn't? [duplicate]

Since the frequency of an electromagnetic wave does not change during refraction but the velocity changes, the wavelength must therefore change. But why doesn't the frequency change in the first place?...
0
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2answers
33 views

Radio Waves / Light: Atmospheric Refraction

The following image differentiates between a visual horizon and a radar horizon. Sidenote: I'm not too familiar with primary surveillance radar technology, but this image refers to secondary ...
1
vote
1answer
31 views

Refractive index and optical fibre question

This is an A level AQA question: A signal is to be transmitted along an optical fibre of length 1200m. The signal consists of square pulses of white light and this is to be transmitted along the ...
0
votes
1answer
43 views

Speed of light dependent on source velocity in other medium [duplicate]

Does speed of light depends upon the velocity of source in a medium (like water) other than space? if yes, does the speed gets added up when the light source moves in direction of light?
0
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0answers
76 views

How does a concave lens form a virtual image?

If rays of light are diverged upon exiting a concave lens, then they have no focal point. The rays completely spread out in random directions. Like diffuse reflection(which does not form an image) So ...
0
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0answers
25 views

Predictions followed from Fermat's Principle, according to Feynman

In his book Lectures on Physics, Feynman mentions two predictions followed from Fermat's Principle (chapter 26-4). 1) Given three media air (1), water (2) and glass (3) with indices measured against ...
0
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1answer
263 views

Determining the refractive index of a glass slab using a travelling microscope

In this practical video of finding the refractive index, the reading is being taken by placing the travelling microscope perpendicular to the slab. But I've learned in another video(Frame Shot) if you ...
1
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2answers
64 views

Refraction of light with destructive interference

The wavelength of light determines it's refraction in a prism. But, what if two beams of light destructively interfere as they pass through a small prism, so there is no apparent wave or wavelength ...
20
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4answers
2k views

Light propagating through a sound wave

We know that the speed of light depends on the density of the medium it is travelling through. It travels faster through less dense media and slower through more dense media. When we produce sound, a ...
0
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0answers
10 views

Velocity vectors during the propagation of photon in elastic scattering question [duplicate]

I have been trouble with the concept of energy of the photon during propagation in random scattered or random continuum medias. E = hf, where E is the energy of the photon in Joules; h is Planck's ...
0
votes
3answers
141 views

How is energy conserved during simultaneous refraction and reflection of light?

My question is regarding the partial reflection and refraction of light when incident on a refracting surface. Here, the energy of Incident Ray is E=hv of Reflected Ray is E=hv and that of Refracted ...
0
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0answers
41 views

What is happening to a wave at a media boundary?

Say we have a light wave going from air to plastic, refractive indexes 1 and 1.5 respectively. What exactly is happening to the properties of the wave and why? Taking wavespeed as v, frequency as f, ...
0
votes
2answers
130 views

What does it mean to say that glass has refractive index 1.5?

The refractive index of a material depends on the wavelength of the light incident upon it which is why dispersion happens. When we say that glass has refractive index 1.5 which wavelength do we have ...
0
votes
1answer
62 views

Speed of electromagnetic wave [closed]

On dispersion , speed of wave is inversely proportional to its wavelength . Therefore, gamma has max speed. But then in visible light , violet has least wavelength still it has least speed in visible ...
1
vote
2answers
106 views

light travels the fastest path of two points, how do you determine those two points?

so in this diagram from Richard Feynman's book: QED Strange Theory of Light and Mater the light takes the fastest path from S to P and the lens makes it so that there are many fastest paths that go ...
1
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2answers
57 views

Is snow falling too fast or too reflective to produce rainbow?

Imagine millions of water molecules suspending in the air starts to turn into snow, I like to know the exact reason why we cannot have snow bow, is it due to the speed of each snow falling very fast ...
1
vote
2answers
77 views

Property of light in different media?

Shouldn't keeping a colored frame in front a flash light ( white light ) change its wavelength or frequency?But I have also learned that light doesn't change its frequency when going from one medium ...
0
votes
1answer
53 views

Curved Light stream?

I was wondering, a while ago, i asked if there is a way to bend light someway, which I got the answer is index of refraction. Which is when light passes through a material it refracts to a certain ...
2
votes
1answer
69 views

What causes these diamonds in water droplets on a screen?

It was raining yesterday and the screen of my iPad ended up covered in varying sized water droplets. As you can see, the smallest water droplets look transparent, and then as the size increases the ...
0
votes
1answer
156 views

Why is the thin prism always in the position of minimum deviation? [closed]

Our textbook says that a thin prism (a prism of angle less than 10°) is always in the position of minimum deviation, but doesn't provide any explanation as to why that it is. What would happen if I ...
2
votes
2answers
88 views

image formation by lenses

Why is the image formed by an object as described in the picture can be derived only from these three ray of lights?Every point on the object has multiple ray of lights going in every direction, how ...
1
vote
1answer
51 views

Focal Power of a Plane Interface

We know that when converging beam of rays are more converging after passing through an instrument, then we say it is of positive focal power. If angle of convergence doesn't change it is of zero focal ...
2
votes
5answers
608 views

Is there a medium less dense than vacuum, in which light can travel faster than $c$? [closed]

Is there a medium less dense than vacuum, in which light can travel faster than $c$? If not, can we make it?
1
vote
2answers
67 views

Why don't images bend when looking through window glass like they do when looking through water?

From this section on wikipedia, the phenomenon of an image appearing warped or slightly displaced when looking through water is due to its index of refraction (1.33) deviating from that of air (~1). ...
12
votes
2answers
461 views

Is it possible to calculate the distance to a rainbow by using the parallax method?

A colleague of mine (a physicist) recently claimed that it is possible to calculate the distance to a rainbow by applying the parallax method and that the result would be ~150 million kilometers, the ...
0
votes
2answers
86 views

Why does purple appear in a rainbow?

It is said that people and digital cameras have color sense only for red, green and blue. So when we see violet/purple in a rainbow, whether with our eyes or in a photo, we should be seeing a color ...
0
votes
2answers
51 views

Working principle of an optical stretcher

I understand that while using an optical stretcher experimental apparatus we attach a small dielectric ball to the specimen of study which can either be a DNA molecule, a Biological cell or any ...
1
vote
1answer
305 views

Why does light bend towards the normal when passing through a denser medium?

When light passes from a medium with less refractive index to a medium with higher refractive index, it bends towards the normal. But why normal . Of course we can take an example of a car moving from ...
0
votes
1answer
110 views

What type of mirage is this?

I am very new to the world of mirages and would like some information as to the type of mirage in this picture which I took this morning. It is the cargo ship African Kalmia which passed my location ...
2
votes
2answers
245 views

Is the reason the sunshine is 'extra bright' after rain due to refraction of the additional water in the air?

Quite frequently after the sun comes out after rain I experience a 30 minute period where the sunshine is 'unusually bright'. Such that it makes my eyes water. My question is: Is the reason the ...
2
votes
1answer
241 views

In refraction how does light interact with electrons if it is not absorbed? [duplicate]

What I (think I) understand: When light is refracted in a medium (say glass), the light interacts with the electrons in the medium and the electrons create new waves. Summing the waves with the ...
0
votes
1answer
44 views

Why do our eyes perceive changes in apparent position of stars as twinkling?

Okay, so we all know that the changes in refractive index leads to continuous changes in star's apparent position but then why don't we see them moving up and down rather than brighten and dim in ...
62
votes
4answers
12k views

What's the physics behind XKCD #2027 (time between lightning flash and radio wave burst)?

XKCD usually has solid (and often contemporary) science behind it. Lightning Difference, #2027 one says: Q: What’s that trick for telling how many miles away lightning is? A: Just count the ...
1
vote
2answers
63 views

what is the refraction index in the upper atmosphere(e.g Theromosphere)?

I've been searching for the refraction index in the upper atmosphere such as Stratosphere and Thermosphere but I can't find it, all that I've seen is all equation without any number that I can use it. ...
0
votes
2answers
90 views

What happens to a light ray after it enters a perfect sphere? [duplicate]

I am assuming a sphere which can reflect, refract and diffuse a light ray. So when a light ray hits the surface of the sphere from outside, a part of it gets reflected, a part of it gets diffused and ...
1
vote
2answers
660 views

What is bent light speed?

I have a question, if there is a straight beam of light that moves at the speed of light, is there a way to calculate the speed of bent light? since bending light causes it to lose momentum? Example, ...
0
votes
1answer
59 views

Why the purple and red light entering the prism is broken at different angles? [duplicate]

Lights entering the prism with different wavelengths at the same angle. why go to different directions? what happens step to step between the protons&electrons in glass and the photons? what is ...