Questions tagged [refraction]
Change in the direction of propagation of a wave when its transmitting medium changes.
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0answers
25 views
Optical path of light [on hold]
What is optical path of light and what is it's mathematical formula?
Is this the correct equation of optical path:
optical path length = (number of waves of light in any medium) x (wavelength of ...
0
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0answers
25 views
Behavior of wave fronts as it crosses a convex lens [on hold]
There is a explanation given in my book regarding behavior of wave fronts as it crosses a convex lens( i.e refraction of plane wave by a convex lens). Here is the thing that's written :-
"When a ...
2
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0answers
35 views
Can the Dirac Hamiltonian accommodate a variable speed of light?
The Dirac Hamiltonian has the form1
$$\left[\beta m c^2+c\sum_{n=1}^3\alpha_np_n\right]$$
where $\alpha_n$ and $\beta$ are Hermitian matrices, and $c$ is the speed of light.
My question: Is there a ...
2
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2answers
20 views
Light hitting a GRIN (Gradient-index) lens at the optical angle
In the image below, rays of light are hitting the GRIN (Gradient-index) lens at the optical angle and then converge towards the optical axis. Why do they do this? The refractive index is only a ...
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0answers
20 views
Light Through Plastic Homework Help [on hold]
I am doing a piece of homework from Isaac Physics, and I have encountered this question:
A beam of light travelling through air is incident upon a sheet of clear plastic of thickness 𝑑=2.80cm and ...
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1answer
48 views
Relative Permittivity in a “Good Conductor”
I have a question in which I need to show that sea water is effectively a "good conductor", when considering the propagation of radio waves of frequency $< 10^9$. We're given that the conductivity ...
1
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1answer
40 views
What causes these diamonds in water droplets on a screen?
It was raining yesterday and the screen of my iPad ended up covered in varying sized water droplets.
As you can see, the smallest water droplets look transparent, and then as the size increases the ...
2
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2answers
77 views
How do we know that light cannot travel faster than it does?
We assume the speed of light in vacuum is its maximum speed but can we not assume that it could be faster, or slower?
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1answer
42 views
Why is the thin prism always in the position of minimum deviation? [on hold]
Our textbook says that a thin prism (a prism of angle less than 10°) is always in the position of minimum deviation, but doesn't provide any explanation as to why that it is.
What would happen if I ...
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0answers
16 views
Normal incidence at a plane dielectric boundary [closed]
How to prove that for glass air interface ($n_2=1.5$ ,$n_1=1.0$) for normal incidence of EM wave reflection and transmission coefficients are $0.04$ and $0.96$?
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0answers
35 views
working to understand virtual images
I'm starting to understand how to use lenses a bit more, but I'm still pretty lost.
I'm building a project that's extremely similar to this one with the implementation. I think my biggest challenge ...
7
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3answers
136 views
What is the speed of a photon in water?
What is the speed of light in water? The speed of light in vacuum, divided by the index of refraction for water. And what is the speed of a photon in water?
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1answer
80 views
Value of complex angle in Snell's law
According to Snell's law:
$$\sin \theta_t = \displaystyle \frac{n_1}{n_2} \sin \theta_i$$
where $\theta_i$ is the incidence angle in medium 1 and (after the ray crossed the interface between medium ...
1
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1answer
26 views
Phase shift for reflection and transmission on absorptive medium with complex refractive index
I am trying to come with a hand-waving explanation as to why the reflection and transmission peaks of a metal-coated Fabry-Perot cavity are shifted in frequency (see the paper by Monzon & al).
...
2
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2answers
44 views
image formation by lenses
Why is the image formed by an object as described in the picture can be derived only from these three ray of lights?Every point on the object has multiple ray of lights going in every direction, how ...
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2answers
69 views
Confusion over Snell's law [duplicate]
Does the angle of refraction always have $n_2$ as its refractive index? As far as I know, $$\frac{\sin\theta_i}{\sin\theta_r} = \frac{n_2}{n_1}.$$
So I got this question here:
Calculate the ...
4
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0answers
84 views
Paint: “Darker When Dry”?
A great question I enjoy bringing up is why are things, in general, "darker when wet". This applies to porous and granular materials like wetted stone, paper, sand etc. It also comes up in painting ...
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1answer
36 views
Is refraction a type of transmission?
I had read a passage somewhere stating that there are three possibilities when light falls on an object. It absorbs some of it, reflects some of it and transmits some (pass through). However, I did ...
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1answer
25 views
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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0answers
21 views
Does light change its color when the refractive index changes? How? [duplicate]
When light passes through materials with different refractive indices $n$, its speed will change to $v = \frac{c}{n}$. Given that $v = \lambda\nu$, either $\lambda$ (wavelength) or $\nu$ (frequency) ...
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0answers
9 views
Propagation of Light in different mediums according to the ray perspective [duplicate]
When a light ray passes from one medium to another, we know that its speed changes. For example the speed of light in a glass slab is not the same as the speed of a ray of light in air or vacuum, but ...
1
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1answer
22 views
How does apparent depth depend on viewing angle?
In derivations of apparent depth and articles on refraction the approximation that the viewing angle is small is made in order to derive that
$$D_a = \frac{n_v}{n_o} D_o,$$
where $D_a$ is the ...
2
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5answers
468 views
Is there a medium less dense than vacuum, in which light can travel faster than $c$? [closed]
Is there a medium less dense than vacuum, in which light can travel faster than $c$? If not, can we make it?
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2answers
56 views
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1answer
48 views
Huygen's Principle, Snell's law and velocity of light
Can you deduce Snell's law from Huygen's Principle without knowing in which medium the velocity is going to less? Of all the derivations I have seen of Snell's law using Huygen's Principle (light ...
4
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1answer
60 views
Is there refraction upon frustrated total internal reflection?
If the incidence angle of a light ray on an interface is greater than the critical angle, but theres a third medium with a higher refractive index than the second, lower refractive medium ~ few ...
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2answers
49 views
Why don't images bend when looking through window glass like they do when looking through water?
From this section on wikipedia, the phenomenon of an image appearing warped or slightly displaced when looking through water is due to its index of refraction (1.33) deviating from that of air (~1).
...
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1answer
44 views
Refractive index of Noble Gases at high pressure
How/where can I find(estimate) the refractive index of noble gases like argon and krypton? How does the refractive index of argon and krypton depend on the pressure, specifically high pressures of up ...
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0answers
32 views
Different index of refraction for different prism
I would like to just know more why different prisms have different index of refraction? From the point of view of atomic physics or something?
I do not seek for full proof and derivation (which is ...
0
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1answer
68 views
What will happen if the refractive index of lens is less than unity? [duplicate]
Generally the refractive index of any lens is greater than air. My question is what will happen if the refractive index of lens is less than unity?
5
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1answer
58 views
Gravitational refraction
I recently used another venue to ask about the speed of gravity, specifically if the speed of gravity is constant or if it is subject to refraction when passing through media, akin to light.
The ...
12
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2answers
318 views
Is it possible to calculate the distance to a rainbow by using the parallax method?
A colleague of mine (a physicist) recently claimed that it is possible to calculate the distance to a rainbow by applying the parallax method and that the result would be ~150 million kilometers, the ...
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vote
2answers
43 views
Focal length of magnifying glass
Why a magnifying glass has a short focal length?
According to its work the object must be between the focus and the optical centre, a large focal length will favour it, then why is it so?
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2answers
59 views
A Question About Brewster's Law
In most textbooks I read, they state that when the angle of reflection + angle of refraction = 90, there is maximum polarization. What I don't understand is what maximum polarization means. Does it ...
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1answer
31 views
A Physics Problem Involving Refraction [closed]
I'm not sure how to solve this problem. I've considered using Malus' law, but then I don't know what theta is, preventing me from solving this problem.
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1answer
1k views
How can the refractive index be below 1 in a dielectric?
Upon checking the optical properties of different dielectrics, I found the interesting case of $Al_2O_3$. It seems to be reported with a refractive index below 1 in the infrared range of $10 - 12~\mu ...
4
votes
2answers
280 views
Snell's law in vector form
Snell's law of refraction at the interface between 2 isotropic media is given by the equation:
\begin{equation}
n_1 \,\text{sin} \,\theta_1 = n_2 \, \text{sin}\,\theta_2
\end{equation}
where $\theta_1$...
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1answer
63 views
Spherical Refracting Surfaces
Why when given a question to find the image of a point object in a spherical refracting surface do you have to consider that there are two surfaces refracting the light?
I assumed that one could ...
2
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1answer
25 views
At Home Experiment Shows Permanent Magnetic Field Does Not Refract
For an at home experiment I positioned a magnetic field so it would cross a boundary from air into water. I wanted to see if it would experience refraction similar to the refraction seen in ...
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4answers
84 views
Refractive index of mirror
What is the refractive index of a common mirror (mercury coated)?
As a mirror completely reflects the light ray, do it have infinite refractive index?
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0answers
29 views
Are impedance matching, wave-vector matching and phase matching equivalent?
Suppose we are considering refraction (if I understand correctly, that is also a type of coupling of light to a second medium). Generally we equate the wave-vector component parallel to the interface ...
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1answer
38 views
Total internal reflection of sine wave vs smooth step function [closed]
If an electric field described by the function
$$f(t)= \begin{cases}
0&\text{if}\ t<0\\
\sin(t)&\text{if}\ 0\leq t\leq \frac\pi2\\
\ 1&\text{if}\ t>\frac\pi2
\end{cases}$$
...
0
votes
1answer
36 views
Why do the sides of my Fish Aquarium look like mirrors?
I bought a new fish aquarium which is square/cuboid in shape.My previous aquarium was spherical in shape. When I filled it with water and put the fish in two of them started acting very stressed so I ...
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2answers
64 views
Why does purple appear in a rainbow?
It is said that people and digital cameras have color sense only for red, green and blue. So when we see violet/purple in a rainbow, whether with our eyes or in a photo, we should be seeing a color ...
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0answers
47 views
What is the upper bound for the index of refraction of space?
It seems that gravitational waves and gamma waves travail at about the same speed, arriving within seconds of each other over distances in the ranges of $10^6$LY. Naively, I would assume this caps the ...
0
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1answer
38 views
Relativistic equations are medium dependent?
Einstein proposed that light travels with a universal velocity from Maxwell's equations on electromagnetism. But light has different velocity in different mediums, so does this imply that the ...
0
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1answer
37 views
Difficulty in understanding an optics question
So here's the question:-
A thin film of transparent material of refractive index $1.52$ and thickness $0.42\ \rm \mu m$ forms a thin coating on glass of refractive index $1.60$. It is viewed by ...
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0answers
38 views
If the velocity of light is different in different medium is it wavelength changes or frequency changes?
We know that the velocity of light is equal to the product of it's wavelength and frequency. And when light goes from vacuum to any other medium it's velocity changes depending the mediums refractive ...
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1answer
19 views
Raise index of refraction of spherical lens
What happens to focal length and aperture of a spherical lens if you raise the index of refraction of the glass?
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1answer
56 views
Complex refractive index and absorption
I have a quite plain and simple question: Why is the imaginary part of the refractive index negative? I read it is to allow a positive sign in case of absorption. But how/why? I don't see why it ...
