Questions tagged [refraction]

Change in the direction of propagation of a wave when its transmitting medium changes. The tag does also apply to index of refraction.

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What causes materials like Vantablack to have their high optical absorption properties?

As per the title of this post. From reading, I understand that blackbody radiation is a factor I should consider here, with light being absorbed and converted to heat etc. However, what I want to ...
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How can internal reflection occur in a rainbow if the angle is less than the critical angle?

In the explanation for rainbow formation, it is said that the spherical droplet refracts and then Totally Internally reflects the incident sunlight. But examining the angles suggest ( see fig below ) ...
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Exponential term obtained while solving the reflectance and transmittance coefficients using the Transfer Matrix method [closed]

I am trying to solve and obtain the percentage values for the reflectance and the transmission coefficient for a four-layer medium-BK7, Gold, Water, and air. The electromagnetic wave which I am ...
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Young's double slit experiment IIT JEE problem

In a Young's experiment,the upper slit is covered by a thin glass plate of refractive index 1.4, while the lower slit is covered by another glass plate, having the same thickness as the first one but ...
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light wave frequency number [closed]

The angular frequency ω and the wavenumber k for light waves travelling within a particular glass medium are related by the following equation 4π2c = Bkω where B is a constant. (a) What causes ...
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1answer
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Snell law with two unknowns [closed]

I having troubles with a basic geometric optics exercise which says: The image shows a glass block immersed in water ($n_\text{water}=1,33$). What it’s the refraction index $n_\text{glass}$ of the ...
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Why are the edges of a broken glass almost opaque?

Unfortunately I broke my specs today which I used in this question. But I observed that the edges are completely different then the entire part of the lens. The middle portion of the lens was ...
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Please explain Q.9 and 13 [closed]

In question 9 how to add intensities? Can we do like first finding 'resultant intensity' from 1 and 2 and then with 3. For that, what do I put the phase difference between the 'resultant' and 3.? And ...
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1answer
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Effective refractive index can be equal zero?

Can someone please explain the cases that the Effective refractive index $n$ on it can be equal zero? Does such a situation even exist? I am trying to solve an ordinary differential equation to find ...
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Resulting ray power after subsequent reflections in a waveguide

Suppose we have a planar waveguide immersed in a solution with refractive index lower than its core. A ray that propagates through the waveguide is depicted below with incident angle (with respect to ...
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Calculate the intensity of light emerging a droplet using calculus

I am reading a paper about rainbow and the appendix here is trying to explain the calculation the author made to calculate the intensity of light. The author mention about it is related to a ...
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Variation of Optical density

How does the optical density of air vary with height. I know about variation of Optical density within smaller heights like that observed in phenomenon of Mirage and looming but when we are concerned ...
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What would be the intensity of light reflected on the interface of denser to rarer medium when the critical angle is not achieved?

There is always some amount of light reflected on the interface of the surface of denser to rarer medium. I just want to know, how much of light is actually reflected and how much refracted depending ...
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Effective refractive index and refractive index [duplicate]

Is there any relation connecting between the effective refractive index $N$ and the refractive index $n$ in waveguide?
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Why do we generally get reflected and transmitted waves that too having same frequency as the incident one?

In a MIT OCW video lecture, a professor discusses a wave on a string having some density moving towards another string. Both of which are joined but have different densities. He goes on to analyse it,...
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Modeling curved light in media with “complex” indices of refraction

I've written an algorithm to solve the Time Difference of Arrival (TDoA) localization problem, using Bancroft's method (see). Given the coordinates of $n$ nodes in ...
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Brewster's angle reflected wave- is it part of the refracted or incident ray?

I am trying to figure out what is happening to the charged particles in the reflective surface in the case of Brewster's angle. When this angle is different than zero or Brewster's angle, then the ...
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Basic understanding of Snell law through three mediums, angles of incidence

I've light traveling through three mediums, so the snell law would be $$n_1\sin{\theta_1}=n_2\sin{\theta_2}=n_3\sin{\theta_3}$$ Suppose that I work with the first and the last equation $$n_1\sin{\...
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1answer
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Polarization by reflection - Brewster's angle

When incident light hits an interface of a dielectric surface at the Brewster angle, I understand that it will result in the generation of a perfectly polarized(horizontally) reflective ray and a ...
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Are there materials that just change the speed of light?

Maxwell's equations in medium without charges read \begin{align} 0&=\nabla\cdot D\,,\\ 0&=\nabla\cdot B\,,\\ 0&=\nabla\times E + \dot B\,,\\ 0&=\nabla\times H - \dot D\,. \end{align} ...
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1answer
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Is it possible to think an example of refraction in which Fermat principle involve a maximum without using reflection?

In a question What is incorrect about the original statement of Fermat's principle? is showed an example of reflection in which Fermat principle involve a maximum, and in comments is said that it ...
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Refraction of a normal incident ray

From the view of law of refraction $$\sin\theta_1/\sin\theta_2=v_1/v_2$$ how can one justify the case that the incident ray enter vertical (normal to the boundary, i.e. $\theta_1=0$)?
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Can we slowdown speed of photons? [closed]

Can we slowdown speed of photons or light? If we slowdown the speed of photon can photon give us mass?
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Path of light ray through varying refractive index

Suppose light ray passing through a medium with refractive index $n=n(y)$. In the case of an inhomogeneous medium in which $n$ varies continuously in the $y$-direction, We have curved rays that ...
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1answer
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What is the magnification of the image produced by a convex objective lens in a refracting telescope

Let's say a refracting telescope with a convex objective lens and a convex eyepiece is viewing a distant object in space. Will the image produced by the convex objective lens be magnified or reduced? ...
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What happens when light travels through consecutively denser mediums?

When light travels through consecutively rarer mediums, total internal reflection happens. What happens when light travels through consecutively denser mediums?
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How does a broadband dielectric Mirror work?

It is widely known that dielectric mirrors work with several layers of at least two materials which differ in refractive index that are layered, such that partially reflected waves interfere ...
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Why are the edges of the shadow so bright?

Today I noticed something while playing with my specs (having diverging lenses). Have a look at it : This is the shadow of my specs on the wall in sunlight. The region of the lens appears darker and ...
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Law of refraction

In my textbook it is given that "The refractive index of a substance does not depend on the angle of incidence" But ...
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1answer
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If we see only the reflected colour, how coloured shadows are of same colour? [duplicate]

We know, for instance, if something is blue, it is because it is absorbing all other wavelengths of coloured light and reflecting the blue colour. But when we pass a white light through a coloured ...
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Why don't we experience objects a little displaced from their actual positions when using eyeglasses as an effect of refraction?

We all know that as a result of refraction,when passing through a transparent/translucent object, the rays get slightly displaced from their actual path. So why don't people who wear eyeglasses ...
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Help deriving optical path

I have to derive the path of a light ray traveling in a stratified medium with linear variation of its refractive index. For context the first two exercises ask you to derive Snell's law using ...
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Pfund effect with white light

One way of measuring the refractive index of a material is using the Pfund effect. I've done this experiment with lasers. However, what would happen if we use white light? Could the refractive index ...
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Why it is necessary that phase of incident, reflected and refracted wave must equal at the interface of two medium?

1.Why it is necessary that phase of incident, reflected and refracted wave must equal at the interface of two medium to satisfy the boundary conditions at the interface? 2. According to boundary ...
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Percentage of light less than the critical angle? [closed]

I am stuck on the following question: "Calculate the fraction of the light incident on the surface with an angle less than the critical angle for total internal reflection" The context of ...
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What is an example of a transparent matter with refractive index less than 1?

I am looking for a concrete example of a transparent matter and wave length of a radiation at which the refractive index of the matter is less than 1 (if they exist, of course). There are several ...
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Why the refractive index increases with salinity?

Suppose I'm using always the same wavelength $\lambda$. Now I start with a beaker with some pure water, and I measure the refractive index. I will get something like 1.332. Now I start adding some ...
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Refraction at perpendicular incidence in Normaski prism?

my question pertains to this: https://en.wikipedia.org/wiki/Nomarski_prism In the diagram shown in the wiki page as well as the diagrams used in the slides for our course, the incident light ray is ...
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How refractive index is related to speed of light in mediums? [duplicate]

Snell's law tells us that, Sine of angle of incident of light by sine of angle of refraction of light, when light travels from one medium to other, is a constant(for that mediums). It is also related ...
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Why apparent position in refraction seems to be raised up perpendicular to object?

When we have a coin in tub of water, the coins seems to be raised up, irrespective of our location outside the tub. Why the shift takes up perpendicular to object?(i.e, if a perpendicular is drawn ...
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Wavefronts, refraction, and the marching soldiers analogy

I am not a physicist, but rather a middle school science teacher. Please be gentle. The marching soldiers has been a really good analogy for explaining why a change of direction is caused by hitting ...
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Why does a qualitative analysis of this question about refraction differ from the answer found through the application of the equation?

Suppose that an object O is in glass ($ \mu $ = 1.5), 6.5 cm from a spherical glass-air interface (from P in Figure 1) where glass is on the concave side and air is on the convex side. In the diagram ...
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Calculating time of flight given index of refraction as a function of depth

Calculating light speed given a simple index of refraction is trivial, of course ($n = \frac{c}{v}$). I'm not sure, however, how one would calculate the 'time of flight' for a light signal in a medium ...
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Why are red and blue light refracted differently if they travel at the same speed in the same medium?

When I look at Snell's law $\frac{\sin\theta_2}{\sin\theta_1} = \frac{v_2}{v_1} = \frac{n_1}{n_2}$ I don't see any reference to wavelength. If red and blue have the same speed in the same medium, why ...
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Zero velocity photon production from receding refractive media?

There appears to be a simple recipe for producing photons with arbitrarily small velocities: Swing a backward facing torch, with refractive index n, around in a circle at c/n. The resulting photons ...
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Is it possible to uniquely identify a diamond by the refraction of light through it?

I am kinda new to physics and this question was bugging me lately. Is it possible in any way to uniquely identify a diamond , maybe through how it refracts light? Do you know if there is any research ...
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Finding refractive index using Snell's law

I was trying to calculate the refractive index of solutions by using a laser pen. I've read that Snell's law can not be used directly if the laser enters and exits the prism. So since the wave changes ...
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Venus light rainbow

I have recently been quite amazed to learn that rainbows produced by moonlight (or moonbows) can sometimes be bright enough to be seen (not with the naked eye though). Now I wonder, would there be any ...
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Definition of the refractive index

My textbook says absolute refractive index of a medium $$n = \dfrac{c}{v}$$ where $c$ is the speed of light in vacuum and $v$ is the speed of light in the medium. Why hasn't it been chosen the other ...
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Can light take a (faster) detour?

I was taught that light tends to take the 'fastest' route. However, this made me wonder about the following scenario: Suppose the start and end point (source and observer) are at the edge of a large ...

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