Questions tagged [reflection]

This tag is for questions relating to reflection, the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. A familiar example of reflection comes from water waves; as the waves travel they reflect off objects that are floating in the water, and also reflect off the walls of the container holding the water.

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How to explain visual phenomena of a moving laser pointer, or an infinite mirror? [closed]

Two really naive questions about two observations from real life that I think are related. Without knowing better, I want to describe them as "seeing/experiencing" the speed of light. A cat ...
Rishi's user avatar
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How do I calculated the second Reflection (2) of light in glass (which equations and tools)

How do I calculated the second Reflection (2) of light in glass (which equations and tools)
Le future de Demain's user avatar
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Complex Refractive Indices, Absorption, and Transparency

A complex refractive index is defined as $n = n_0 + \kappa$ where $n_0$ is the "standard" refractive index, and $\kappa$ is the optical extinction coefficient. The optical extinction ...
Chris Gnam's user avatar
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When a transverse wave in a string reaches a free end [closed]

For ex. A frictionless, massless ring on a rod. Why does the ring go up a distance two times the amplitude of the wave? I have read the other question similar to this one but still haven't found an ...
Jyot's user avatar
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Lenses and missing reflection

I am wondering why reflected rays are not considered with lenses. If a ray strikes a surface, another is reflected off that striking point; however, this is not added when studying lenses, only ...
DisD's user avatar
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Fresnel Equations, Refraction, and Metals

I'm trying to make sense of how the fresnel equations apply to metals. Here are a few of the things I believe I understand: All reflections of light occur specularly. When an object appears to ...
Chris Gnam's user avatar
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Fresnel Equations and an Opaque Surface?

I'm trying to make sense of what actually happens to light when it interacts with an opaque surface. The fresnel equations give us the proportion of light which is reflected off the surface of a ...
Chris Gnam's user avatar
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Final image formation in these 2 cases:

Can someone please explain simply how we determine how many times we have to consider reflection and refraction to obtain final image. Example a: Here they only considered refraction twice to obtain ...
Alex Aboda's user avatar
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1 answer
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Energy of evanescent wave in total internal reflection

We know that the reflective coefficient in total internal reflection is 1, which means that all energy is reflected. But we also know that for evanescent wave, Poynting vector in the direction ...
km12180202's user avatar
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Keplerian telescope with parabolic mirrors

Is it possible to arrange two off axis parabolic mirrors (OPAs) to transform the emitted rays of a point source into a collimated beam, as in the figure below? That is, similar to a Keplerian ...
tush's user avatar
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Perceiving the rainbows

Famous Astrophysicist Dr Neil DeGrasse Tyson, explains that whenever we observe a rainbow it appears exactly semi-circle to us. If another person is observing the same rainbow from a slightly ...
Shamant Desai's user avatar
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Using Fermat's principle to derive the Cartesian paraboloid

I am self-studying Optics by Pedrotti and I'm on the subject of geometric optics, specifically ideal Cartesian surfaces. These are reflecting or refracting surfaces that form perfect images. I was ...
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Plastic cup filled with water shiny surface [duplicate]

When I hold a plastic transparent cup half filled with water and see it from above then its sides (up to which water is filled )appear shiny. Some of my fingertips (which are holding glass ) are wet ...
Zrancon's user avatar
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What happens to a single photon in case photoexcitation doesn't occur upon "hitting" an electron of a single atom

I'm having trouble finding sufficient answers that don't boil down to discussing materials. Some people say that if a photon does not excite an electron it doesn't interact with it at all and just ...
bansheenocturno's user avatar
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2 answers
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Can any mirror arrangement give an optical advantage?

I'm trying to see tiny movements in a membrane using a laser spot that shines on it, and looking at the reflected spot. I was wondering if it is possible for any plane mirror arrangement to give me ...
Rishab Navaneet's user avatar
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Reflection of light by edges and corners of mirrors

Suppose I have a point object placed between mirrors inclined at angle $\theta$ with each other. What will happen to the ray that strikes the junction point of these mirrors? I'm looking for a ...
StudiousElectron's user avatar
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What is the albedo of our Sun?

I think the Sun is the closest to a perfect natural black body we can get in the Solar System, if so then what happens to the light if I point a laser pointer at the Sun?
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Non-reflective material becomes reflective why? [duplicate]

Why an object (which is opaque) and non reflective becomes reflective if seen from a certain angle . Like I was seeing grey plastic it became reflective when I saw it at a near parallel angle to ...
Aditya Mishra's user avatar
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How can evenescent coupling work if an evanescent field cannot transport energy?

This youtube video shows a simulation of evanescent coupling between a driven optical fiber and another that is not driven. I had never heard of evanescent fields so I looked it up on Wikipedia, where ...
Ethan Reesor's user avatar
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Reflection from a spherical surface

I am self-studying Optics by Pedrotti and I'm stuck on the algebra for an example of spherical reflection. We have a point source at O that reflects off a spherical surface and creates a virtual image ...
nwsteg's user avatar
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Free particle encountering an infinite potential barrier

I understand that a wave function cannot penetrate through a barrier that has infinite potential. However when the wave function reflects off from the barrier what does this look like? If we're in a ...
selin's user avatar
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Where is the reflection of a point height $h$ above the surface of lake formed? Inside the lake or on its surface? [closed]

It’s a trignometry question where a point is located at height $h$ above a lake, and it’s angle of elevation from a point P located 60 m above surface of lake is 30 and angle of depression of the ...
Aarti Makhija's user avatar
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Equation of a reflected wave at a fixed end

If $y1=Asin(kx-wt)$, it is identical with $y2=-Asin(wt-kx)$. But then if I write a reflected equation of y1, it is -Asin(kx+wt), whereas the reflected equation for y2 becomes Asin(wt+kx) since both ...
Moon's user avatar
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Why did Einstein include reflection of light from a moving mirror in his paper? [closed]

Einstein, in his 1905 relativity paper, allocates a section to the issue of reflection of light from a moving mirror and derives three formulas (angle, frequency, energy). What was his reason or ...
Maesumi's user avatar
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Infinite reflection inside a glass loop

If you had a loop made of completely transparent glass (or other material), in the shape of a donut; think atomic collider (but probably not needing to be so large :) ), and you introduced light from ...
Steve Knowles's user avatar
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It's about the apparent position of anything in case of refraction

So my question is that,what actually the apparent position of let's say a coin in water seen by us is?? It's a small experiment in textbooks that take a coin in a shallow and wider bowl and mark the ...
Neha Bharti 840's user avatar
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1 answer
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Why is deep open ocean blue?

If we assume the ocean is sufficiently deep so that the blue light transmitted inside the water gets absorbed completely before it reaches the ocean floor and be scattered back towards the surface, ...
Meatball Princess's user avatar
2 votes
1 answer
113 views

What is the speed of light in case of Critical Angle?

When light travels from an optically denser to a rarer medium, it bends away from the normal and at a specific angle of incidence, the angle of refraction is ${90}^{\circ}$. When the angle of ...
Rishith Raj Raizada's user avatar
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Why does focal length of a concave mirror $f=-R/2$?

When both the distances $R$ and $f$ are measured from mirror only they shouldn't be of sm sign? When we take it negative in mirror formula that I understood... But why here I'm confused
Pranjal Bajaj's user avatar
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Schlick's approximation for reflectance when $n_1 = n_2$

another raytracer here. I'm using Schlick's approximation to the Fresnel equations, which is said to be reasonably faithful. I'm a little puzzled about the situation where the incident ray is just ...
orion elenzil's user avatar
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Magnification of closely packed thin lenses, or of closely packed lens and mirror

I was taught how to calculate the equivalent foci in both the cases. And since the formulae resemble the simple mirror and lens maker formulae, teacher said that this system is behaving like a single ...
Gautam's user avatar
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3 votes
1 answer
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Why are the surface of most liquid so reflective?

I saw a puddle of water on the road and I noticed that I can very clearly see the reflection on its surface in almost 8k high definition of each cars and buses that drove by. I went to the canteen and ...
user6760's user avatar
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Plain mirror reflection confusion

Can anybody help me reconcile my understanding of plain mirror reflection with what is said in this video? instagram video My understanding is that image size is always the same as object size but in ...
greenplasticdave's user avatar
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2 answers
65 views

Penetration/Reflection properties of metals exposed to EM waves

I've read many questions being answered about how electromagnetic waves (being visible or not) can be reflected and/or absorbed and/or passed through objects. I know some waves penetrate through paper,...
Bikay's user avatar
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1 answer
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Electromagnetic waves reflection?

I have a couple questions regarding the EMW (in my case, 2.4–2.5 GHz) reflection: Could dialectric materials reflect electromagnetic energy, and how does this impact the efficiency of such reflection?...
AlexGenesis's user avatar
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2 answers
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What are the reflective properties for 77 GHz electromagnetic waves (automotive RADAR)?

Automotive radar uses electromagnetic waves around 77 GHz frequency. Is there some data, tables available about the reflectivity of such waves for various materials, like water, stone, people, metal ...
Alex's user avatar
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2 answers
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Doubleslit (single slit and a mirror)

Imagine a setup similar to a doubleslit but it has only 1 slit and the other slit is just a reflection on a mirror. Will I still get interference pattern despite only 1 real slit?
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Mirror momentum in a Mach-Zehnder interferometer

As I understand it, the mirrors in a MZI should gain momentum from the reflected photons. How much momentum should the mirrors get for a single photon? In a simple photon-mirror incident at $\pi/4$ ...
PiedPiper's user avatar
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Reflections from both edges of a finite well

In section 11.3.1 in Richard Robinnett's Quantum Mechanics book, it says that in the case of transmission resonance ($T=1$), there's complete destructive interference between waves reflected from the ...
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Is the specularity of a material a fraction of its total reflectance?

Specularity is a value that defines how glossy or matt a surface is. For example, a mirror is highly specular, but a brick wall is not. Is the specularity of a material a fraction of its total ...
Camilo Diaz's user avatar
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The use of Corner reflector and beams to find the distance between moon and earth and light Divergence?

I am about to start college and my knowledge regarding both beams and retroreflectors is close to nonexistent , but from what I read a corner reflector is a device that reflects waves back to its ...
lodo's user avatar
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1 vote
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Two-Ray Ground-Reflection Model: Understanding the Difference in Phase Offsets at the Receiver

Currently, I'm trying to understand the Two-Ray Ground-Reflection Model. During my research, I came across the following simplification expressing the received power as follows (taken from Wikipedia): ...
Henerii's user avatar
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3 votes
1 answer
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Help with sourcing a specific type of integrating sphere

I am looking for a specific type of integrating sphere that can be used to capture diffuse reflectance measurements, and I would appreciate help with locating a commercially availably version of this ...
aferrie's user avatar
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Is it preferable to say $v$ is " image distance " than to say " image position " in spherical mirror formula?

I was going through spherical mirror formula $1/v + 1/u = 1/f$ where $u$, $v$ and $f$ are named as object distance, image distance and focal length respectively. But while using this equation we do ...
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Is reflected color not from the wavelength corresponding to that color?

I was reading through Josef Albers' interaction of color (a classical art color theory book), where he makes this point: If I see a substance, or pigment of a particular color, doesn't that mean I'm ...
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How to calculate refractive index $n$ from absorbance, transmittance or reflectance spectra? [duplicate]

I have absorbance (Abs), reflectance (R%) and transmittance (T%) data of $\rm TiO_2$ deposited tin film on FTO glass substrate. The data was collected using UV-Vis spectrophotometer. How to calculate ...
Mona's user avatar
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6 votes
2 answers
538 views

How smooth must a surface be to produce specular reflection, and do Lunar boot prints meet this standard?

Question: How smooth must a surface be to produce specular reflection, and do Lunar boot prints meet this standard? A recent post on Space Exploration asked why footprints on the moon displayed ...
Woody's user avatar
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Measuring reflectance of a non-planar object w/ an integrating sphere

I am designing an experiment to measure the reflectance (diffuse+specular) of insect specimens, and I plan to use an integrating sphere to collect the measurements. Typically, I have seen that ...
aferrie's user avatar
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2 votes
0 answers
68 views

What are the Fresnel formulas for acoustics?

While it's not too difficult to derive Snell's Law for acoustics e.g. from Huygen's principle like for light, I find surprisingly little resources on an equivalent to Fresnel formulas linking the ...
Tobias Kienzler's user avatar
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2 answers
71 views

Does Law of Reflection gets violated?

I was curious as to why the "Law of Reflection" is only a law and not a principle. Are there any specific conditions or circumstances where it is not followed by chance? If so, how so? Note: ...
Parth Sareen's user avatar

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