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2answers
30 views

Calculate required power output for a laser

How to calculate power rating required for a laser in order to produce a dot at a specific distance after reflection? For example, the laser is 10cm from the mirror, at an angel of 30 degrees it ...
0
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1answer
32 views

Optical system for cloning an image of a light source?

I need to create an optical system for cloning an image of a light source to human eyes. Is there a correct solution(design) for this problem. Reflectivity of the mirrors must be equal. Because ...
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1answer
42 views

Would we see the past if we look to a mirror 1 light year away? [duplicate]

What would we see if we place a mirror 1 light year away? Would we see the present or the past?
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2answers
44 views

How would a plane hitting a ball move (opposite of Pong)?

When a moving ball hits a stationary plane at an angle of incidence to the normal, it bounces away at the same angle (the angle of reflection), which is commonly understood. My question is 1) What ...
3
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1answer
20 views

Wave interference on window film coating

"The windows in an office tower are coated with a film to minimize reflected light of wavelength 550 nm. If the glass has an index of refraction of 1.52 and the film coating has an index of refraction ...
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1answer
20 views

Distinguishing between perfect rigid mirror and symmetrical universe

I have a relatively bizarre question which I'm not even fits into the category of mainstream physics, but here I go anyway. I want to consider two hypothetical situations. Then I want to see if there ...
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0answers
15 views

Phase change by reflection [duplicate]

Let's consider a light ray falling on a cuboid made of glass at the angle $\alpha$. Then there will be a reflected ray $A$. The ray will also refract. Let the refracted ray be $B$. Ray $B$ will be ...
1
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0answers
22 views

What is the “Obscuration Factor (OBF)”?

In a paper I am reading for my master thesis I came across this "obscuration factor (OBF)". The authors indicate that it is a measurement of the average intensity of reflection. They do not give a ...
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1answer
36 views

Surfaces that reflect UV rays

I've been trying to research what surfaces reflect UV rays for the past day but it's been difficult coming up with definitive answers. So far what I've found is that surfaces that reflect visible ...
4
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1answer
31 views

What causes these rainbow effects using a polarizing filter on an airplane?

I know that light reflected from a surface at 45° is polarized and that for a similar reason skylight arriving from a direction orthogonal to the sun is polarized too. Photographers make use of this ...
0
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0answers
31 views

Would you be able to see yourself in a mirror in front of you as you two are in a room traveling at the speed of light? [duplicate]

Veritasium talked about this in one video. If you are in a room or a train, plane, car or whatever just a closed space traveling at the speed of light and you put a mirror in front of you, could you ...
0
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1answer
27 views

Metal Refractive index

I'm working on Fresnel equation for calculation of reflection of a light (532 nm) on Iron. I've got a question: Is metals refractive index always a real number or it can be a complex number?
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2answers
85 views

Why does the light instantly disappear when we switch off the source?

For example i take a box which is completely covered by the most perfect mirrors possible inside and inside that box i have a bulb whose bulb holder is also covered with the most perfect mirrors ...
2
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0answers
26 views

Model of scattering in wet things

You know that clothes and some surfaces become darker when wet (covered in an earlier question: why wet is dark?), because of the disordered reflections or of the refractive index of water or ...
0
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1answer
36 views

What is the phenomena where an object is repeated in a glass surface?

I don't understand why this happens. Is the image being repeated because the light is being bounced back and forth on the multifaceted surface?
2
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1answer
59 views

Probability current in scattering problems

This is a section from Wikipedia: In regions where a step potential or potential barrier occurs, the probability current is related to the transmission and reflection coefficients, respectively ...
0
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1answer
42 views

Light absorption for different liquid

when I was working on a cylindrical glassy bottle that filled with water, I found that the initial light intensity is less than the final light intensity. (It's clear but I experiment this) This is ...
0
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1answer
24 views

Why does light reflected on water tends to 'smear' in the vertical direction? [duplicate]

I have noticed that in city lights reflected on the water are very often smeared more in the vertical direction (relative to the reflecting plane I presume), than in the horizontal direction. See, for ...
1
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1answer
35 views

Can a virtual image created by a mirror have position in front of the mirror?

I dont think so, because then the rays will intersect and the image will be real. Please let me know if you know a case in which a virtual image is formed in front of the mirror.
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2answers
70 views

Can gravitational waves resonate?

Can gravitational waves resonate? - Perhaps by creating standing wave interference in a cavity? Could that feasibly happen either in nature or by engineering?
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2answers
30 views

Ideal mirror properties [duplicate]

Suppose there is sphere which is completely made of ideal mirror. What if a light particle is induced in it by a source of light? Does the light particle remains there by bouncing or disappear after ...
1
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2answers
63 views

How to calculate reflection profile of a beam shining onto a moving mirror?

I want to build a projector, where a beam of light is shining on to mirrors, placed at different angles, which are spinning fast enough to draw lines. The question is, how to calculate the needed ...
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0answers
34 views

Explanation for strange atmospheric phenomenon

OK, I've seen this strange thing in the sky sometimes. Not all that often, but sometimes. It actually happened tonight. On most nights, at say 9 P.M. it is dark. There might be stars, moon, ...
1
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1answer
141 views

Are reflection and transmission coefficents real or complex?

Is it common practice to give reflection and transmission coefficients as the ratio of the respective waves with respect to the incident wave when written in complex form or real form? I have seen ...
0
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1answer
34 views

Can an aluminized blanket hide a person from thermal cameras? [duplicate]

Well, if the person is wrapped tightly I expect the answer is "no", but could an aluminized loose "cloak" hide a person from thermal imaging cameras by reflecting the cold surroundings? Or, if the ...
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0answers
42 views

Reflection and refraction of light [duplicate]

When a light ray strikes an interface a part of it gets reflected, a part of it gets absorbed while another part gets refracted. Why does light reflect? Why does it refract?
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0answers
39 views

Maximum laser power that mirror can handle?

Can I use standard mirrors used for lasers used for laser shows to build some laser that has higher power and is able to burn materials? What are power and power density limitations that cannot be ...
1
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2answers
58 views

Why does the thought experiment of a photon bouncing of a mirror imply anything for other objects?

Okay, so I am reading a book, "The Elegant Universe" by Brian Greene, which talks about motion and its effect on time. Greene makes the point that time changes with motion by saying that if you have ...
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0answers
20 views

absorption and reflection of sound on molecular level

Can someone explain the reflection and absorption of sound on the molecular level? What really is reflection? Why porous and soft material absorbs sound? What's the definition of soft in terms of ...
1
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0answers
49 views

What is the total reflectivity/transmissivity of a pack of a semi-transparent glass sheets [closed]

Consider a pack of $N$ layered semi-transparent parallel glass sheets (like a 'cake'), each having the reflectivity coefficient and thickness $(r_k, d_k)$ for $k=1 \dots N$. Consider a light beam of ...
2
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1answer
48 views

light falling on a completely reflecting friction less mirror

If you had a perfectly reflective mirror whose face was perpendicular to the ground and was kept on a friction less track on the ground, and you shined a flashlight on it, what would happen? Would ...
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votes
1answer
525 views

Laser, wire, and a circle of light

So, when I point a laser at a piece of wire (pointed at a specific angle), a circle of light appears on a wall behind it (see image below). I am trying to see why this happens and if there are any ...
3
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3answers
166 views

How to understand this symmetry in the wavefunctions of a diatomic molecule?

In Wikipedia (and elsewhere), a particular symmetry of the quantum system of a diatomic molecule is mentioned: symmetry under reflection along a plane containing the internuclear axis. The ...
4
votes
3answers
194 views

How to arrange mirrors so I can't see myself?

If I wanted to surround myself with mirrors how would I need to arrange them so that if I stood in the middle of them I couldn't see myself in any reflection? For simplicity let's just say we only ...
0
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1answer
84 views

Reflection in a cylindrical mirror

Suppose I have a completely cylindrical surface which is silvered on the inside. I want to know what type of reflection takes place when an object is placed inside the ring. Does infinite reflections ...
2
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1answer
163 views

Huygens' Principle During Reflection: comparing wavelets from before reflection with wavelets from during reflection

I was recently reviewing geometric optics, during which I read about Huygens' Principle and how it could be used to prove the Law of Reflection from the "light is a wave" viewpoint. I'll quote what I ...
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2answers
57 views

Phase change on reflection only 0 and $\pi$ allowed

We know that when a wave on a string is reflected from a hard boundary, the phase change is $\pi$, and from a soft boundary, the change is 0. My question is: this two conditions (hard and soft ...
1
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1answer
94 views

Basic rule for diffraction

I'm a high school student. I still don't understand the reflection, diffraction and refraction of light. It seems to me that in concept of quantum physics, reflection is just a process of object ...
2
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2answers
129 views

Rainbow reflected on TV screen? (pic attached)

According to wikipedia, A rainbow is an optical and meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets... Given that we require ...
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2answers
80 views

Why does black glass reflect better than white one?

Why does black glass reflect better than white glass? Both of them are glasses, so they reflect light. But why black glass reflects better? See below, shiny black glass.
0
votes
1answer
74 views

How do you calculate the focal point location of a circular mirror? [closed]

I'm trying to find the focal point and center of curvature of a concave mirror. Just using the radius for the center doesn't seem to work. I know C = 2f, but I'm not sure how to find f or C, given the ...
1
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0answers
56 views

What happens when light is reflected from a surface moving in a medium with a huge refractive index?

Imagine a mirror is moving away from a light source in a substance through which the speed of light is very slow -- so slow that the speed of the mirror is close to being the same as the speed of the ...
0
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1answer
34 views

How does one show specific thickness and wavelength determine full transmission of electromagnetic waves?

How does one show that thickness and wavelength determine the full transmission between two different dielectric media if the boundary condition equations between two dielectric media are independent ...
0
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2answers
68 views

Does a reflecting object move faster than one that does not reflect?

Suppose you have two objects with the same mass and shape, such as a ball, and the only difference between the two is that one reflects light and the other does not. Would one object's velocity be ...
0
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0answers
17 views

Are images formed at the focus at all conditions?

The picture shows the image formed between c and the focus when the object is placed beyond the centre of curvature(c).But my question is since all parallel rays falling on a spherical mirror must ...
-1
votes
2answers
50 views

When does a monochromatic beam of light on a reflective surface get completely transmitted?

My book says when when a monochromatic beam of light is normally incident on reflective surface it gets completely transmitted. I am bit confused could you explain me?
0
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2answers
92 views

Capturing a light beam

For a given container made of an extremely reflective surface, is it possible to shine a beam of light in, and with no 'fiddling' (i.e. closing the hole, tilting the object) to contain the beam for an ...
3
votes
2answers
98 views

How would a sound mirror work?

Context: We all know that by galvanizing a plate with a silver coating, this plate will have a very high reflection coefficient and act as a mirror for EM radiation (not for all $\lambda$ ranges of ...
18
votes
3answers
2k views

Why is the light reflected at the same angle from mirror?

From the school physics I know that the material objects bounce from the plane surface at the same angle, losing some kinetic energy. In the same school I was taught that the light (and waves in ...
1
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0answers
82 views

Law of reflection for a moving mirror

An elementary fact that people learn about mirrors is the law of reflection, that the angle of incidence of a light beam striking the mirror (as measured with respect to a normal) equals the angle of ...