Questions tagged [refraction]

Change in the direction of propagation of a wave when its transmitting medium changes.

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6k views

Do electromagnetic waves always move in straight lines?

When we send an electromagnetic short wave to the sky, it reflects due to the ionosphere effects. But if we send it horizontally, is it correct that it moves around the surface of the earth, and if it ...
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130 views

Phase difference and optical path difference (OPD)

My textbook says that $\frac{\delta}{2\pi}=\frac{\Delta L}{\lambda}$, where $\delta$ is the phase difference and $\Delta L$ is so called path difference. But that's a cheat in my opinion. Even if the ...
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Why does the angle of waves change in refraction instead of just altering the relative position of each component the medium?

So, first of I would like to apologize if my question is at all stupid, I am not at all good at physics, but I do quite enjoy studying and learning about it. So I know about refraction, I'm aware of ...
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573 views

Radio wave behaviour in reflection, Refraction and Diffraction

I am trying to understand how radio waves behave when reflected, refracted and diffracted. I have put together a list based on light which I think will be the same. Can anyone tell me the behaviour of ...
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313 views

How is horizontal atmospheric refraction explained?

I can understand vertical atmospheric refraction due to a gradual change in the refractive index of air. The distances measured in this model are often great. Sun moon planets etc.. now the question I ...
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Will myopic vision be improved while diving?

Why does my myopic vision improve under water while wearing a diving mask, compared to my normal vision on land?
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How large will my buddy's eyes appear underwater while wearing goggles?

My buddy and I are underwater scuba diving. We are both wearing diving masks. I know an object in the water will appear 1.33 times larger. But how large will my buddy's eyes appear inside of his ...
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1answer
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Why does the soap bubble shine with the colours of the rainbow?

Is it because of refraction of light in water? a mixture of UV rays in sunlight? polarization of reflected light? interference of light reflected from external and internal film surface? or maybe ...
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320 views

Examples of mediums which are not linear, homogeneous and isotropic

In electromagnetics we are taught that mediums can be linear/nonlinear,isotropic/anisotropic,homogeneous/non-homogeneous...we also learn their definitions. Now we are told that if nothing is specified ...
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Path a photon or phonon takes in a moving medium

Lets say we have a medium with refractive index n whose velocity is given as a function of height. $v_x(y)=ay$ How would we go about finding the motion of a photon or phonon in this space from the ...
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476 views

What does the refractive index for e.g. alpha mean?

When I look for some materials like https://en.wikipedia.org/wiki/Barium_sulfate and want to extract the refractive index then there is written: (nD)=1.636 (alpha). And sometimes also for beta and ...
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If two different mediums have the same refractive index do they refract light identically at all wavelengths, pressures, etc.?

Is it possible to differentiate between two substances purely based upon how two mediums refract different colors of light? It is clear that different elements absorb (and emit) light very differently ...
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N00b path integral formulation question

I have a question about the path integral formulation used in QED etc. The path integral formulation implies to me that index of refraction (and reflection or anything also calculated using this ...
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Deriving the law of reflection for a moving mirror in relativity

I am following a training course and came across this proof, from my colleague, that the ordinary law of reflection $\theta_i = \theta_r$ does not hold in relativity: Let $S$ be a perfectly ...
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3answers
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If I were to change the definition of refractive index

We know that the Refractive Index is just a number that gives an idea of how much velocity of light decreases in comparison to vacuum. So, it makes sense to define a variable, n as: n=c/v where v ...
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1answer
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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 ...
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1answer
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Are Fresnel Equations with Complex Indices and Angles always valid?

This question-answer pair came after i was asked the following question and realized i had to do some research of my own to answer it fully, and to be sure that the answer is „yes“, in the sense ...
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Is their a way to protect screens from being recorded? [closed]

This idea might sound stupid but... Is there a way a screen would be impossible to record using a prism? I’m not talking recorded by a software but recorded from a camera… If you put a prism layer in ...
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1answer
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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 ...
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1answer
642 views

Question on real image formation by light

Before starting a detailed tour of physics, I wanted to clear some of my basic doubts. I have studied the image formation by mirrors and lenses and I'm aware that a real image is formed of an object ...
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1answer
312 views

Formation of a rainbow

Why the formation of rainbows require a total internal reflection on the part of light. I mean can't the rainbows be formed without it , simply through refraction by the water droplet at a suitable ...
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3answers
621 views

Index of Refraction in Metal: Approximating Complex Perturbation

If you consider waves in a metal, you can write the index of refraction for the metal as, $$ n^2 = 1 - \frac{\omega_p^2}{\omega^2} $$ I am interested in what will happen if the index is perturbed by ...
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What is the main difference of a sound wave propagating in air and in water?

I was reading this article out of curiosity and I started wandering about the key difference in the propagation of a sound wave in water. Maybe something due to the fact that very rarely we have a "...
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Optical Path Length

Recently I have been studying Waves and Optics and I am stuck trying to understand what the optical path is and how it is derived. Specifically, my notes tell me that the optical path difference is $$...
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1answer
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The concept of force carrying photons

Are the force carrying photons really something physical? Do they really occur during electromagnetic interactions? Does this mean that in different mediums where the speed of light differ, the ...
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2answers
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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 ...
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Error propagation in sine

Having little experience teaching uncertainties and error propagation to high school students I am learning a lot of new things this year. One thing in the textbook we use states that the uncertainty ...
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1answer
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Can a rainbow be seen from above?

I saw this picture of a "rainbow from above" Based on what I understand about rainbows, some googling and my experience chasing them, if I saw one and try to fly above it, the phenomenon will ...
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1answer
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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 ...
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Refraction and Internal Reflection

When a light is incident on the boundary of a medium with an angle greater than the respective critical angle, we obtain the angle of the refracted or reflected ray to be equal to the angle ...
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Refraction and critical angle on a prism

I shouldn't be stuck on this, and I'm sure there's a simple way of doing this but can't seem to find it. I am doing a problem Which involves a light ray entering a glass prism which is an isosceles ...
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1answer
498 views

Under water light reflection of air in a cup vs water in a cup

The last time I was on vacation I was drinking on the swimming pool, and after I was finished with the drinks I started playing with the 2 plastic cups I had, and noticed that the air produces a ...
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How are classical optics phenomena explained in QED (Snell's law)?

How is the following classical optics phenomenon explained in quantum electrodynamics? Reflection and Refraction Are they simply due to photons being absorbed and re-emitted? How do we get to Snell'...
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Rayleigh scattering light intensity

Assume a single ray of unpolarized light propagating through an opaque medium (water). Due to absorption and Rayleigh scattering the intensity decreases and light gets scattered/diffused before hiting ...
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1answer
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Refraction in oil and plastic

Can some one help me in understanding this picture. I came across this interesting picture in wikipedia on Refractive index. when green light is refracted in plastic it looks like reddish orange and ...
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1answer
26 views

The change of focal distance as a result of adding a substance

I have a given focal distance between lens and an image sensor (in air). Now I add a protective glass with a known refractive index and width between the lens and the sensor. How can I calculate the ...
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346 views

Glasses underwater

So I figured the refraction of the cornea is based on the index of air and the vitrous humor to make a perfect image. Underwater this is messed with because water has the same index as the eye. Hence ...
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Quantum Electrodynamics explanation for refraction [duplicate]

I am trying to understand the fundamentals of Quantum Electrodynamics through the simple example of refraction. Let's start with a plane wave coherent state (or a number state) impinging on a boundary ...
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If colour A bends more away from normal than colour B when it passes from a denser to a rarer medium? Which colour is slower in second medium?

Will it be colour A or colour B? I learnt that more it bend, slower its speed would be. Will be true when the light passes from a denser to a rarer medium? Or will it be true only when the colours ...
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Fermat's principle of least time for reflection and refraction [duplicate]

In discussing geometrical optics, Fermat's principle of least time is often used to solve problems and is generally used as a replacement of laws of reflection and refraction. Fermat's principle is ...
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1answer
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Why can't two truly identical experiments on quantum scale give the same result?

When we refract light on air/water interface, some part of light is reflected while some of it gets refracted. My question is when we consider light as a photon and send it (photons) one by one, what ...
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Changing the refractive index of biological tissue using Radio Frequency (RF)

I have been looking into changing the refractive index of a specific medium initially using Ultrasound in a known location via a mechanical Doppler shift of the emitter (Mahan et al., 1998) which has ...
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4answers
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Changing Refractive Index

Is it possible that the refractive index of a material could change?if so,what are those factors and what kind of variation could they bring?
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1answer
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Why do the LINES in a vertical soap bubble get thinner as we go down?

I understand that the soap bubble gets thicker at the bottom of the bubble due to gravity, resulting in a complicated array of different colors of different wavelengths being constructively and ...
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Measuring inner choke point on non-uniform silica capillary tube

I hope this is an appropriate place to be asking questions like these (google brought me here when I was searching for a solution)! I make an assembly where a small silica capillary tube (OD of 1mm) ...
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Difference between the increase in optical path due to refraction and that due to reflection

If we place two glass plates of refractive index $\mu$ and each having thickness $t ,$ on the way of a light ray the increase in the optical path becomes $$ \left(S_2 P - S_1 P \right) = 2 \left(...
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1answer
671 views

Equations of Fermat's principle/Snell's law in a gradient lens (sugar aquarium)

I'm trying to animate a beam of light inside a substance with gradient index of refraction as a function of y. A good example of that is a syrup inside an aquarium like here https://www.youtube.com/...
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2answers
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Are there any real-world examples of refraction of light by magnetic permeability?

The question Fresnel Transmission Coefficient for Magnetic Field is interesting. Thinking about it led me to reflect upon what little I know of the history of optics, with refraction by lenses and ...
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Why does a rainbow only form with a 42° angle? [duplicate]

Why do rainbows only form with a 42° angle? Is there something special about this angle?
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1answer
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Dielectric constant change in the atmosphere?

I'm curious about the refractive index changing in the atmosphere. As I understand it (and I may very well be wrong/naive) when a ray of light enters from one medium into another, the electric field ...