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2
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1answer
43 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 ...
0
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2answers
28 views

How are different wavelength components collected by the same detector in a spectrometer?

Let's think, we have a detector array (128x1 and each CMOS detector responds 400 to 1000 nm TSL1401CL that way, each detector has 4.6875 nm interval). Then, basically in a spectrometer a prism reflect ...
0
votes
1answer
23 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 ...
0
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3answers
46 views

Mirrors and the human eye

Not sure if this is a suitable question for this exchange. Me and a friend are debating what can be seen through a periscope consisting only of two 45 degree mirrors. My friend tells me that the ...
7
votes
4answers
9k views

What is the color of a mirror?

A mirror couldn't be white, as then you wouldn't be able to see your reflection so clearly. It wouldn't be transparent, as that then won't reflect. So what color is it?
3
votes
1answer
51 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% ...
3
votes
2answers
135 views

A mirror in the sky to look at past Earth

Earth reflects light from Sun into Space; are there any "mirror like" objects which reflect back to Earth this light? Has anyone been able to use this method to recover some information on how was the ...
1
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0answers
15 views

Fresnel equations of reflection applied to microparticles

I wanted to know if the Fresnel equations of reflection, as described here, can be used to calculate the reflectance on the interface of particles which have a diameter near the size of the wavelength ...
0
votes
2answers
77 views

Bragg diffraction and lattice planes

Crystalline substances show, for certain sharply defined wavelength and incident directions, very sharp peaks of scattered X-ray radiation. From the illustration below we see that we get constructive ...
0
votes
1answer
65 views

Total internal reflection for perpendicular incidence

Are there any materials, which give total internal reflection for perpendicular incidence? Here, by this phenomena I mean: no absorption (including for evanescent propagation inside), finite ...
0
votes
0answers
31 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 ...
3
votes
1answer
27 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
vote
1answer
50 views

Increase contrast on the image taken by CCD camera

I project a pattern on a reflecting object and I capture the reflected pattern (reflected via the object) using a CCD camera. However, the reflected pattern has a very low contrast (due to volume ...
1
vote
2answers
58 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 ...
1
vote
0answers
52 views

Help understanding Fizeau's calculation of speed of light

While searching for different methods of calculating Speed of light, I came across one of the methods that Fizeau discussed below which I cannot fully understand. In short, in Fizeau’s apparatus, a ...
9
votes
1answer
1k views

Would the inside of a black hole be like a giant mirror?

As any light reflected or emitted from objects inside a black hole (if it is possible to be there) does not leave the event horizon and comes back inside, would it be like seeing yourself? What I ...
1
vote
2answers
75 views

Given two surfaces, one that absorbs light and the other that reflects it, will there be a signficant temperature difference?

My likely wrong understanding of light is this: By some way the molecules are structured, a photon hits an atom or a structure, is absorbed, then re-emitted and it's that photon wavelength that I see ...
-1
votes
1answer
38 views

Total internal reflection angle [closed]

For what angle does total internal reflection happen? I think that it happens for angle=k*pi where k is an integer with the possible values: 0, 1, 2, 3... Is my assumption correct?
1
vote
2answers
85 views

How is the image in a mirror created? Are there infinitely many light rays?

How is the image in a mirror created? Are there infinitely many light rays? My motivation for the question is from image processing. We work with images as discrete 2D functions, as matrices. Spatial ...
0
votes
2answers
106 views

Light-Matter Interaction and Object's Appearance

I am taking a course in Computer Graphics, and the teacher said we could put materials in there main categories: mirror like glossy or specular diffuse He suggested that the law of reflection is ...
1
vote
2answers
495 views

Colors in the secondary rainbow reverse of that in the primary rainbow

Why the colors of Secondary rainbow is reverse of that in the color in the Primary rainbow? What can be the possible reason among the following options Because it is formed by one internal ...
3
votes
3answers
585 views
17
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7answers
4k views

Why do solar panels not have focusing mirrors?

Most of the solar panels that I have seen do not have any mirrors, etc., but usually solar cookers have mirrors. What is the reason for solar panels not having focusing mirrors?
1
vote
2answers
36 views

What is the phase shift incurred by a sound wave as a result of reflection?

While studying waves I read the fact that a sound wave gets shifted by $\pi$ as a result of reflection against a surface. But I am unable to prove that fact. Assuming the interface to be a node I can ...
0
votes
1answer
145 views

Semiclassical description of EM waves reflection from metallic surfaces

Imagine an EM wave impinging on a metal. Fresnel's formulas tell us that no wave can propagate through the metal, or that the transmitted field is an evascent wave with some penetration depth ...
0
votes
0answers
20 views

Particle collision: relationship of incident and reflected particles [duplicate]

A photon traveling through a curved fiber optic cable advances by reflection, yes? If each reflection is the product of a collision between the incident photon and, say, a wall particle that ...
185
votes
17answers
61k views

A mirror flips left and right, but not up and down

Why is it that when you look in the mirror left and right directions appear flipped, but not the up and down?
10
votes
2answers
379 views

a weird image of sun

Have you ever notice the sunset's image in the sea? It's like long light path to the end of the horizon! I've attached a sample of this: How can we explain this? I know that it can happen even in ...
2
votes
3answers
2k views

How to calculate the temperature of a receiving point from concentrated solar power?

I'm exploring a DIY project about solar power and have found very few resources that can explain, in a not too simple but not too advanced way, how to go about calculating important values in solar ...
9
votes
2answers
265 views

Is reflection instantaneous?

I was wondering while reading "On the Electrodynamics of moving bodies" by Albert Einstein (1905) (Translated to English). In the paper, he describes the time as being: by definition that the ...
23
votes
6answers
3k views

Why did high quality mirrors use aluminum coatings instead of silver?

I have two questions on mirrors. I’ve read that in the past quality mirrors were coated with silver but that today vacuum evaporated coatings of aluminum are the accepted standard. When I look at ...
0
votes
1answer
35 views

What temperature is achieved in focus point by 5000 flat 1x1cm mirrors onto a satellite dish?

There is this video ("R5800 Solar Death Ray") where teenager built a 5000 mirror device which concetrates the solar rays which is showing the potency of the mosaic method of concentrating sunlight ...
5
votes
5answers
2k views

Focusing Light with Flat Mirrors

What is the best way to focus (sun)light using flat mirrors? My goal is to start a fire. Cutting the mirrors is easy.
7
votes
1answer
514 views

The physics behind Google Glass' “prism”

In writing a bachelor's thesis about applicable use cases for Google Glass in retail I also strive to explain the physics behind Glass' optics. So far I've come to the following conclusions: Glass ...
3
votes
2answers
124 views

Why can't we reach the ends of rainbow?

Rainbows are spectacular things. But I imagine why we can't reach to the ends of rainbows. Do rainbows have no ends ? If so, why can't we reach at them? If you go closer,they will go further. Why?
0
votes
0answers
22 views

Which wavelength of light can reflect easiest on any material?

What I know is, when wave has long wavelength it tend to penetrate matter. While a short wavelength tend to be absorbed So what is the medium value of wavelength has most probability to reflect? And ...
1
vote
3answers
565 views

Light Ray Reflection from concave mirror

Suppose a ray of light hits a concave mirror and is parallel to the principal axis but far away from it such that it doesn't follow paraxial ray approximation. Will it pass through focus or between ...
1
vote
1answer
46 views

One way mirrored hollow sphere [closed]

Imagine a one way mirror, where from one side it appears to be glass, but from the other side, it appears to be a mirror. Now, fold that sheet into a hollow sphere, so the inside is mirror (and I'm ...
1
vote
2answers
30 views

Is the temperature rise caused by reflection of sunlight linear?

I have saw a YouTube video showing large Fresnel lens can focus sunlight into a spot which can melt iron. I am very interesting of that, but large Fresnel lens are not that popular, so I was ...
1
vote
0answers
36 views

Frequency dependance of sound wave reflection

Why are high frequencies reflected more than low frequencies off an 'acoustically hard' surface such as concrete? I basically understand that the amount of reflection is determined by the impedance ...
2
votes
1answer
64 views

When two plane mirror are inclined at 60° to each other?

How many images will be formed? In the case above I think 5 images will be form. But how can I exactly find out the number of images if the inclination angle is different. Is there any formula or it ...
0
votes
0answers
64 views

Off-Axis Parabolic Mirror Elliptical Collimated Beam Shape

When you collimate a point source using an off-axis parabolic mirror (OAP) with a circular shape, the beam area of the collimated light becomes more and more elliptical (x-dir. is smaller than y-dir.) ...
1
vote
0answers
65 views

Use mirror to see every angle around me

An applied physics question: How can I setup a mirror all around an arm wrestling table so I can see all angles of what I'm doing? The arm wresting table looks like this With the wrestlers on ...
7
votes
1answer
224 views

Does a wave experiencing a total internal reflection penetrate the medium in any way?

Let me explain my concern usingn this picture: At the point of total internal reflection does a fraction of the wave get into medium 2? I would imagine it should happen because of the uncertainty ...
4
votes
1answer
65 views

How do mirrors look & behave atomically?

I was observing mirrors recently and I was thinking about how an mirror would look atomically. I was always used to looking at atoms as being colored that said, I was always concerned at how they ...
2
votes
3answers
122 views

What “exactly” happens when a ray is incident at the critical angle?

The question arose when my physics teacher taught me geometrical optics and told that the phenomenon of both refraction and $reflection$ occur by change in medium. First of all, I'm not sure about the ...
0
votes
1answer
34 views

Does adding water on convex mirror increase its power?

What is the comparison between the power of convex lens in air and in water ? What causes the change in its focal length
0
votes
1answer
60 views

Is the glass made up of holes that let the light to go through it?

The following passage has been extracted from the book "The Magic of Science-A.Frederick Collins" (1917): Substances of all kinds have pores or holes in them. A sponge has pores that can be ...
1
vote
1answer
55 views

Why is the focal length of a convex mirror negative?

According to the Cartesian sign convention, the focal length should be positive since the convex mirror forms a virtual image to the right of mirror (positive direction) when light comes from left. ...
14
votes
2answers
2k views

Is it possible to 3D print a mirror to create a high quality telescope?

Is it possible to 3D print a mirror with todays available materials? If so, would there be a reduction in image quality?