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Questions tagged [refraction]

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

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Help understanding the speed of light in media with refractive index < 1

I have read the standard explanations on this, but I still have trouble with convincing myself that information is not propagating at faster than the speed c in media of refractive index less then ...
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Total reflection and the direction of magnetic force [on hold]

I have the following two simple questions: Say we have a cylindrical glass filled with water. The height of this glass is 10 centimeters, its radius is 1 centimeter. We but a source of light on the ...
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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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Question about transmission of paraboloidal light waves in bi-convex lens

The question is as follows: Show that a paraboloidal wave centered at $z_1$ is converted by a lens of focal length $f$ into a paraboloidal wave centered about $z_2$, where $\frac1{z1} + \frac1{z2} ...
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Do photons “bounce off” of electrons?

I’ve been reading a book, and in one part the author explains how electrons only absorb the wavelengths of light that can take them to an excited state, i.e. that can take the electrons to a higher ...
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1answer
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How do I use a sunstone? How does it work?

I have acquired two pieces of Icelandic Spar (optical calcite) with surface and internal fractures that should be serviceable as sunstones. I have observed the double refraction and cancelling double ...
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How do we determine refractive index of a photonic crystal?

Normally, refractive index of a medium is defined as $$n=\frac c{v_\text{p}},$$ where $c$ is the speed of light in vacuum, and $v_\text{p}$ is the phase speed of light in the medium. Phase speed is ...
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Why does the intensity of the scattered light vary when a monochromatic laser is shined into a transparent object?

When a laser is shined into a glass ball such as this video (link) or a bottle of water (link) the light is refracted through the whole transparent body. However, the intensity of the light scattered ...
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Is speed of light continuous when entering a medium?

I know that light has the speed $c$ in vacuum and speed $c/n$ in a medium with refractive index $n$. I wonder how this exactly happens - is there some kind of smooth transition? If so, on which scale?...
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Why doesn’t a normal window produce an apparent rainbow?

When light refracts in a prism it creates a rainbow. My question is, why don’t all windows or transparent objects create this dispersion, i.e. why is the refractive index dependent on frequency in a ...
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Polishing Spherical Refracting surface vs Lens

My text book states that When we polish a spherical refracting surface (sphere) it doesn't behave as spherical surface and mirror .It still behaves as spherical surface. The polished side is just ...
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1answer
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(7) Will a nearsighted person who wears corrective lenses in her glasses be able to see clearly underwater when wearing those glasses? [closed]

Will a nearsighted person who wears corrective lenses in her glasses be able to see clearly underwater when wearing those glasses?
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Physical Analogs of General relativity and optics

My Prof told me today there is a 1-1 correspondence between particles in a curved space time, and optics problems in various indices of refraction, extending even as far as black holes. Does anyone ...
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2answers
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Why does a prism refract light into a rainbow? [duplicate]

Why does a prism refract light such that the different frequencies of light “spread out”? The same goes for rainbows, why do the raindrops “spread out” the different frequencies of light?
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1answer
49 views

Why light travels through shortest path during refraction?

I know in order to compensate with change in speed but how does Light actually know which path is less dense or more dense?
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4answers
69 views

Why does frequency remain unchanged in light refraction but wavelength doesn't? [duplicate]

Since the frequency of an electromagnetic wave does not change during refraction but the velocity changes, the wavelength must therefore change. But why doesn't the frequency change in the first place?...
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2answers
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Can light possibly bend to the other direction of the normal?

When light goes from a more dense medium to a less dense medium, it bends away from the normal, as in the image When light goes from a less dense medium to a more dense medium it bends towards the ...
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Radio Waves / Light: Atmospheric Refraction

The following image differentiates between a visual horizon and a radar horizon. Sidenote: I'm not too familiar with primary surveillance radar technology, but this image refers to secondary ...
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Why doesn't the wave's frequency change as it gets refracted? [duplicate]

I know that frequency means a complete wave produced per second. But when the wave gets refracted, it's wavelength decreases. If the wave's wavelength has decreased doesn't it means that the wave has ...
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Dielectric constant in terms of fundamental forces [duplicate]

How can one explain the slowing down of electromagnetic waves travelling in a medium using fundamental forces of nature like electromagnetism?
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1answer
69 views

Do clouds reflect radio waves?

Do clouds reflect radio waves? Specifically, those waves used in radars. And, what kind of matter refracts or reflects radio waves?
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Raytracing on convex spherical surface, where n1>n2

I'm reading my textbook and I'm trying to figure the ray tracing of a single point of this one case that the book doesn't cover. My question is, what does the ray tracing look like when we have a ...
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1answer
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“Partial” Total Internal Reflection

Can partial TIR happen? Consider the image present in this link Here, at point D, TIR happens, but also there is transmission. Is "total" internal reflection a misnomer?
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Lorentz invariance of Maxwell's equations in matter

I know that Maxwell's equations of electromagnetism are Lorentz invariant in a vacuum. But what about in a generalized medium, e.g. a metal, a rubber, a dielectric, a magnet? I have read it comes down ...
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1answer
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Is it possible to calculate the refractive index of a gas mixture given the pressure, temperature and wavelength?

I am searching for a formula to calculate the refractive index at a specific point in a planetary atmosphere. Given are pressure, temperature, wavelength and the molecular composition of the ...
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0answers
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Quantum mechanics of refraction and reflection? [duplicate]

I learnt that light bends when passing through different mediums is due to the epsilon which is how much the strength of electric and magnetic field in the direction of travel changes in the material, ...
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0answers
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Will the refractive index of a electrolyte change when chemical reaction happens?

Since polarization is the reason of refraction, then anything that changes the structure of molecule, atom, or electron will present as a change of reflection. Thus, to my understanding, chemical ...
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1answer
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Does light travel faster in between Casimir plates?

Speed of light is in general $c/n$ where $n$ is a refractive index. But for example introducing two parallel plates with very small spatial separation will perturb the energy density of vacuum ...
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1answer
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Griffiths Electrodynamics Problem 9.39: How can $\sin(\theta_T)$ be greater than one?

When an electromagnetic wave strikes an interface between two linear media, Snell's law states that $\frac{\sin(\theta_T)}{\cos(\theta_I)} = \frac{n_1}{n_2}$ where $\theta_I$ is the angle of incidence,...
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1answer
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Photoelastic modulator vs. Acousto-optic modulator

I am trying to understand the salient differences between photoelastic modulators (PEMs) and acousto-optic modulators (AOMs). Both of these devices are based on the photoelastic effect - that is, ...
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1answer
29 views

Refractive index and optical fibre question

This is an A level AQA question: A signal is to be transmitted along an optical fibre of length 1200m. The signal consists of square pulses of white light and this is to be transmitted along the ...
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2answers
64 views

Refraction of light from going to one medium to another

On the basis of ray theory can somebody please explain my why does light bend from going to one medium to another.Why can't it move in a straight line but with different speed ?
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How to theoretically calculate refractive index of a gas?

All the resources I've seen on calculating refractive index of gases appear to give equations with various "magic constants", i.e. the equations are fits to experimental data. But I'd like to ...
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1answer
64 views

How does temperature affect the refractive index of a vinegar?

I’m conducting an experiment on the relationship between temperature of vinegar and its refractive index.
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Rainbow angle equals tropics inclination… a coincidence?

An observer from ISS can find a rainbow forming under certain conditions ( of internal reflection /refraction) in a cloud of water droplets at the equator. It may be regarded as equivalent to a ...
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2answers
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Variable refractive index question [closed]

A ray of light travelling in air is incident at grazing incidence on a slab with variable refractive index, $n (y) = [k y^{3/2}+ 1]^{1/2}$ where $k = 1 m^{-3/2}$ and follows path as shown in the ...
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1answer
26 views

Variation of Refractive index

We know that refractive index, for any medium, $$n=1/\sqrt{\epsilon\mu}.$$ Also, according to Cauchy's relation $$n=A+B/\lambda^2,$$ where $A$ and $B$ are constants related to the medium. ...
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1answer
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Speed of light dependent on source velocity in other medium [duplicate]

Does speed of light depends upon the velocity of source in a medium (like water) other than space? if yes, does the speed gets added up when the light source moves in direction of light?
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1answer
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Calculating refraction between numerous media

Last year, our teacher made us an exam to check our knowledge in light reflection and refraction. I don't perfectly remember it, but I know that one of the exercises included a ray with its angle of ...
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0answers
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Zebra and Donkey Watching [closed]

Suppose I have a white donkey in front of me. Say i paint black stripes on the objective of my camera lens and click a photo of it. The context of this question is that when we cover a lens ...
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1answer
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Image formation in Ray Optics

Can a refracted ray and a reflected ray form an image( different incident rays coming from the same object, one sufferning reflection and other refraction)? What is the criteria for forming an "image"...
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Refractive Index in Ionized Liquid from Micro Aspect

I learned about the refractive index of gases and dense materials, which is a function of the atom number per volume, wavelength of electromagnetic wave, etc. However, what is the refractive of ...
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Does phase change occurs on refraction at a lens?

There is no phase change between refracted (transmitted) rays and incident rays, according to boundary conditions of electric field and magnetic field, in accordance with the Maxwell's equations and ...
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How does a concave lens form a virtual image?

If rays of light are diverged upon exiting a concave lens, then they have no focal point. The rays completely spread out in random directions. Like diffuse reflection(which does not form an image) So ...
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1answer
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Can light be sped up to go 30 times fast than the speed of light in a medium?

Here's the link: https://sciencebulletin.org/researchers-develop-way-to-control-speed-of-light-send-it-backward/ Here's the line that makes no sense to me: Abouraddy and study co-author Esat Kondakci ...
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1answer
104 views

Why can't $ε_r<1$ (at low frequencies)?

I've heard it said that the vacuum permittivity is the lowest possible permittivity for any substance, that no substance can have $ε_r<1$. Is this true? If so, why is this different from ...
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Predictions followed from Fermat's Principle, according to Feynman

In his book Lectures on Physics, Feynman mentions two predictions followed from Fermat's Principle (chapter 26-4). 1) Given three media air (1), water (2) and glass (3) with indices measured against ...
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1answer
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Determining the refractive index of a glass slab using a travelling microscope

In this practical video of finding the refractive index, the reading is being taken by placing the travelling microscope perpendicular to the slab. But I've learned in another video(Frame Shot) if you ...
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0answers
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Different Refractive indices in Anisotropic medium

In an anisotropic medium, if we consider the dielectric tensor to be diagonal and medium is isotropic in $\mu $ or ($\mu = \mu_0$). Then from fresnel equation we get a quadratic equation in 'n' (...
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1answer
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TIRF mycroscopy with intermediate layer of different refraction index

I`m currently experimenting with through the lens TIRF microscopy in which an additional layer is used between the glass and the sample. This 10-30 μm layer has a higher refraction index than my ...