Questions tagged [refraction]

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

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289 views

Condition for constructive interference of light question

The question was asking me to find an expression for the constructive interference between light which follows the paths $PQ$ and $PRS$, once the light has reached the air outside of the two glass ...
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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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Can relative permittivity be less than 1?

Relative permittivity shows that force of interaction in some media is 3 times less than in vacuum ($\varepsilon = 3$) for example. When looking tables of permittivity I never saw a value less than 1. ...
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Mirages under water?

In Polynesian shallow water, the temperature difference from short place to place is so high that one can see the same trouble refraction that exist in air above fire or metal sheet in summer. So I'm ...
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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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Stellar aberration in a water-filled telescope

I read that when the stellar aberration of light is measured with the help of a telescope filled with water, the value of the aberration is equal as in the case of a telescope filled with air. Just ...
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Difference between scattering and refraction?

I while back I learnt that when light is incident on a dipole the dipole will scatter the light, and when it is incident on a material of a different refractive index then the light refracts. From the ...
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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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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 ...
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Refraction of light with destructive interference

The wavelength of light determines it's refraction in a prism. But, what if two beams of light destructively interfere as they pass through a small prism, so there is no apparent wave or wavelength ...
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Is the refractive index neglected in the standard Michelson interferometer equation: $\lambda=2d/N$

Hoping someone can help with this. It's a simple question, but I can't seem to find the answer anywhere: I'm looking at the basic Michelson interferometer experiment, where you measure the wavelength ...
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Formation of a second image due to reflection at a boundary

To determine the refractive index of a transparent plate of glass, a microscope is first focused on a tiny scratch in the upper surface, and the barrel position is recorded. Upon further lowering ...
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Reflection coefficient derivation

from fresnel equations we have $$r_{parallel}=\frac{n_1\cos\theta_i-n_2\cos\theta_r}{n_1\cos\theta_i+n_2\cos\theta_r}$$ $$r_{perpendicular}=\frac{n_2\cos\theta_i-n_1\cos\theta_r}{n_1\cos\theta_i+n_2\...
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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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How to calculate the refracted light path when refraction index continuously increasing?

Suppose an incident light from vacuum ($n_1=1.0$) into some media ($n_2=n_1+\mu\; x^2$) as in the figure below. How to calculate the refracted light path curve in closed form? Update: Try to set up ...
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The ideal shape of a plano-convex lens

What's the type of the ideal shape of a surface of a plano-convex lens to focus a parallel beam at the point? Considering the lens turned its flat side to a beam. Surely it must be aspheric: ...
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Can Snell's law be said to fail in this condition?

I ran into a question in my textbook which asks me "when does Snell's law fail?". My first reaction was that it's a law, it can't fail but they gave the solution as the condition when light rays are ...
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Why do prism split light at angle instead of curving it?

I assume that when light goes through matter, it doesnt really slow down, but the waveform is pushed back due to some resonance with the atoms. EDIT: Interference is probably a better word than ...
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Relation between intensity of light and refractive index

The intensity of light (as calculated from time average of the poynting vector) is given by $I = (1/2) \epsilon v E_0^2$. Here the intensity is dependent on the velocity of light in the medium. The ...
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117 views

Which colour comes out first from a prism?

When a narrow beam of white light is incident on a triangular prism. The speed of red light is maximum and violet is of minimum, red light bends less and travels less distance as compared to violet ...
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Gravitational lensing, indices of refraction and the size of the universe

Been pondering the following question for over 15 years now. Is it possible that the size of the universe has been over estimated due to the effects of gravitational lensing and boundary indices of ...
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Which of these 2 methods for calculating the focal length of a concave mirror is more accurate?

I have done an experiment to measure $f$ the focal length of a concave mirror. I have a list of 8 values for $u$ the object distance and 8 values for $v$ the corresponding image distance. I ...
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608 views

Real and apparent depth not looking perpendicular to the interface

What is the formula for Real vs Apparent Depth, when not looking perpendicular to the interface? I know the formula $$\frac{\text{real depth}}{\text{apparent depth}}=n$$ but I'm not looking for ...
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Apparent depth and virtual image position [duplicate]

Why does the virtual image appear right on top of the object and not a little to the right, for example? Is it explained by some formula or just symmetry of the geometry?
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Bending of light Ray in radially varying refractive index [duplicate]

If light passes near a massive object, the gravitational interaction causes a bending of the ray. This can be thought of as happening due to a change in the effective refrative index of the medium ...
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Velocity vectors during the propagation of photon in elastic scattering question [duplicate]

I have been trouble with the concept of energy of the photon during propagation in random scattered or random continuum medias. E = hf, where E is the energy of the photon in Joules; h is Planck's ...
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Maxwell's equations, nonlinear media, and dynamic response

Maxwell's equations in the vacuum with electric permittivity $\epsilon_0$ and magnetic permeability $\mu_0$ are given as: $$\nabla \cdot \vec E = \frac{\rho}{ \epsilon_0}$$ $$\nabla \cdot \vec B = 0$...
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Why Ewald–Oseen extinction theorem failed to explain refraction

One way to understand the refraction of light other than Huygens–Fresnel principle is by Ewald–Oseen extinction theorem, which states that light scatters only in forward direction with a slower ...
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173 views

How is the image distance negative?

Following is a problem from book: "The near point of a person's eye is 53.0 cm. To see objects clearly at a distance of 24.0 cm, what should be the focal length of the appropriate corrective lens?" ...
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How is energy conserved during simultaneous refraction and reflection of light?

My question is regarding the partial reflection and refraction of light when incident on a refracting surface. Here, the energy of Incident Ray is E=hv of Reflected Ray is E=hv and that of Refracted ...
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Speed of electromagnetic wave [closed]

On dispersion , speed of wave is inversely proportional to its wavelength . Therefore, gamma has max speed. But then in visible light , violet has least wavelength still it has least speed in visible ...
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Why does a laser beam stay coherent when it passes through glass?

If I have a coherent laser beam and I shine it through some glass, the light will slow down because it will interact weakly with the atoms in the glass. However, the beam that comes out the other side ...
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Microwaves in other media

I saw a video on how microwaving grapes make plasma. He said that the refractive index of microwave is about 10 inside the grape. Now, we don't know the wavelength of the microwaves in the grape or ...
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How does every ray of light or photon can follow the same Snell's law in a very random states of matter like gases and liquids?

We know that to study refraction at the interface of two media, we use Snell's law which is $$μ=\frac{\sin(i)}{\sin(r)}$$ or $$μ=c/v$$ (for vacuum as one of the media). I know this is an ...
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Aether atmospheres [closed]

http://arxiv.org/abs/1004.1467 claims to have an alternative explanation of the interaction of light around massive objects. Many of the general-relativity-tests such as bending of light near a ...
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Refraction of a circular polarised wave

I'm trying to derive the expression for the fields $E_{1}$ and $E_{2}$ in terms of $n_{1}$, $n_{2}$ and $E_{0}$. Where: $E_{0}$ Is the incident field amplitude of circular polarised light $E_{1}$ Is ...
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Mathematics supporting the classical explanation of why the phase speed of light slows down in a medium

Consider the answer here by Chad Orzel which explains how a monochromatic light can slow down in a medium. He explains, You can think each of the atoms (of the medium) as being like a little dipole,...
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Refraction on the edge of mediums

Say I have this setup : Here a light ray (in red) is incident on the point A in such a way that it is collinear with AB, and the indices of refraction are as mentioned in the figure. So my question ...
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How To Calculate Wavefront Error of a Lens

The wavefront describes the Optical Path Difference (OPD) of an optical system. Typically the OPD has the unit of microns. The OPD is the difference of the Optical Path Length (OPL) of an arbitrary ...
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What is happening to a wave at a media boundary?

Say we have a light wave going from air to plastic, refractive indexes 1 and 1.5 respectively. What exactly is happening to the properties of the wave and why? Taking wavespeed as v, frequency as f, ...
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What does it mean to say that glass has refractive index 1.5?

The refractive index of a material depends on the wavelength of the light incident upon it which is why dispersion happens. When we say that glass has refractive index 1.5 which wavelength do we have ...
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What is Cherenkov radiation? [duplicate]

What is Cherenkov radiation? I came across this concept when I was learning SR. Why can't particles moving at speed of excess of speed of light in the medium. Why it does not violate the limitation ...
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Can light in a medium travel faster than speed of light $c$ in vacuum?

Refractive index of medium $m$, $n_m$, is given by $$n_m = \sqrt{\mu_r\epsilon_r}$$where $\mu_r$ and $\epsilon_r$ are permittivity and permeability of the medium respectively. And, velocity of light ...
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The Speed of Light and Its Medium's Density

When reviewing a refractive index chart there is a relationship to the density of the medium and the velocity of electromagnetic radiation through the medium. The lower the density the greater the ...
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Where does Light go if it is in a glass prism and why?

I know that photons/light bends or bounces when it hits glass so if it was in a glass prism where would it go. I know that light/photons hit the glass at different angles and if it hits at almost a ...
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Does TIR obeys laws of reflection?

After reaching the critical angle, do Snell's laws and laws of reflection hold good?
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Geometric optics multiple lenses

I am confused on how light rays behaved in this figure, specifically when it passed through the diverging lens. Why would the light rays converge when it passed through the diverging lens, when it ...
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Amplitude of wave

Does amplitude of wave changes during refraction of wave If it will changes,why? I have been searched for internet but still cannot find a complete answer
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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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light travels the fastest path of two points, how do you determine those two points?

so in this diagram from Richard Feynman's book: QED Strange Theory of Light and Mater the light takes the fastest path from S to P and the lens makes it so that there are many fastest paths that go ...