Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [refraction]

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

-1
votes
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
votes
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
votes
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
votes
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 ...
0
votes
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 ...
0
votes
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
vote
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
votes
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?
0
votes
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 ...
-2
votes
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 $0.96$?
1
vote
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
votes
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?
0
votes
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
vote
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
votes
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 ...
0
votes
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
votes
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 ...
1
vote
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 ...
-1
votes
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 ...
0
votes
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) ...
0
votes
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
vote
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
votes
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?
0
votes
2answers
56 views

Huygens' principle

How do we know that the angle ADC is right angle here?
1
vote
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
votes
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 ...
1
vote
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). ...
0
votes
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 ...
1
vote
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
votes
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
votes
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
votes
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 ...
1
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?
0
votes
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 ...
-1
votes
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.
18
votes
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 $\theta_1$...
1
vote
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
votes
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 ...
1
vote
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?
0
votes
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 ...
0
votes
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 ...
0
votes
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 ...
3
votes
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
votes
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
votes
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 ...
1
vote
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 ...
0
votes
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?
1
vote
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 ...