All Questions
Tagged with refraction geometric-optics
245
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Luneburg lens in a medium
A Luneburg lens is a spherical lens with a gradient refractive index. It has the interesting property that light coming from focal length of infinity will be focused on the surface of the lens.
The ...
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votes
2
answers
135
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What does the optical Hamiltonian mean?
So I was trying to demonstrate Snell's law with Hamilton's equations, and when I got the Hamiltonian:
$$H = -\sqrt{n^2-p_{1}^2-p_{2}^2}.$$
I had a question about what this Hamiltonian indicates. I ...
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25
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How to Calculate Focal Length when in another medium?
How do you calculate the focal length of a lens when it is placed into another medium, if I only have the focal length of a lens in the air? I understand that the lensmaker's equation should be used, ...
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What is a convex-concave lens?
I came across this term while studying for optics, and I'm unsure as to what this means. My thinking is that it might be a meniscus lens, but the text separately give two different models for each ...
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Behaviour of light in non-Newtonian fluids
So if a ray of light is passed through a cuboidal glass tub, and refraction occurs for the first time and if force is applied on the the fluid laterally, the viscosity would vary and so would it's ...
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2
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Why total reflection happens at only 1 angle?
The critical angle can be intuitively understood by Snell's law.If the incident medium has a bigger diffraction index than the refracted medium then according to Snell's law the refracted ray will be ...
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How do parallel reflected rays meet to form image at infinity? If they never meet then how is image formed?
In my textbooks it is written that when an object is kept at focus, its image is formed at infinity and is real. But how is this possible because parallel lines never meet and it is necessary for rays ...
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Lens maker’s formula from parabolic approximation
I’m attempting to derive the lens maker’s formula for a thin or thick lens using the parabolic approximation.
I’m familiar with the other proof using the law of refraction and different angles.
The ...
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2
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Is there a way to calculate the angle between the refracted and reflected rays given the refractive index?
Is there a way to calculate the refracted and reflected rays? I know we use Snell's law to calculate the refracted rays, but is there a formula to calculate the angle of the reflected rays, or does it ...
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Apparent position of object in bowl of water
Say you have a bowl of water and you keep an object in it. What would the apparent position of an object inside the bowl from the position of an outside observer? Will the curvature of the spherical ...
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Difference between deviation of ray and wavefront
This is a reference to the question posted by
Govind Prajapat Refraction of light through a slab of variable refractive index
A monochromatic light wave is incident normally on a glass slab of
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Finding the limiting refractive index of a rainbow
Give the limiting refractive index of a rainbow.
The raindrops are modelled as spherical droplets, with refractive index $n$, with parallel rays from the Sun incident on it. I have a very limited ...
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1
answer
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Lenses and missing reflection
I am wondering why reflected rays are not considered with lenses. If a ray strikes a surface, another is reflected off that striking point; however, this is not added when studying lenses, only ...
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answer
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Snell's Law- Extraordinary ray
I applied the snell's law to find the angle of refraction of the Ordinary and Extraordinary ray. And I got the correct answer 3.51. But I know my approach to the question is wrong because I applied ...
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answer
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Magnification of closely packed thin lenses, or of closely packed lens and mirror
I was taught how to calculate the equivalent foci in both the cases. And since the formulae resemble the simple mirror and lens maker formulae, teacher said that this system is behaving like a single ...
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As we all know a convex lens doesn't exactly converge all rays parallel to it's axis on a single point. So I want to find one such figure
Writing a differential equation for such a figure is an uncomplicated task. It can be accomplished by using snell's law. But the resulting equation probably isn't solvable. I put it in wolfram alpha ...
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Is it possible to witness a rainbow while facing the sun?
We know that a rainbow occurs due to the refraction and reflection of light inside raindrops. We also know that inside spherical raindrops total internal reflection is not possible. So some light is ...
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Do Normal Incidence contradicts the definition of refraction?
Professor told our class that if someone wants to define refraction in words, it can be done as the following, The deviation of light from its path when it passes from one medium to another is called ...
user380777
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I need to figure out the length of a crystal to move a light beam [closed]
I need to figure out the length of a crystal to move a light beam shining through it.
The height is known, and so is the refractive index of the crystal and its length. What I can't figure out is the ...
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Use of sign convention two times in ray optics
In this particular derivation of refraction happening at a spherical surface in terms of its radius of curvature , image and object distance and refractive index is done by my book as shown
When we ...
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Why is there only one angle of incidence that gives minimum deviation in prism?
On plotting the angle of deviation vs the angle of incidence for a prism, we find that the graph dips only at one point. It is this result that is later used to prove that for minimum deviation to ...
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How to increase the angle of light (without going from a higher to lower index of refraction)?
I would like a device to spread out/increase the angle of rays in a light source. In other words, I would like to reproduce the behaviour of light traveling from an area of higher to lower index of ...
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Why does the green light change to red in the prism? [duplicate]
I know that white light, upon entering another medium from air/ vacuum, disperses into its constituent colours. Essentially when travelling in the air, all of the constituent colours have the same ...
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A Rainbow Paradox
I was studying the phenomena of the formation of a rainbow. In my book, the following diagram is given:
So, the rays at the red end of the spectrum make a larger angle with the incident ray than the ...
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1
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Combined reflection and refraction [closed]
Suppose a plane mirror is half-submerged in another medium (say water) and light rays are incident obliquely on mirror at the interface separating two media.
My questions -
(a)- Will reflected rays ...
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2
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Why double rainbows have the orders of the color bands in them inverted?
I did some online search and found the explanation using the following two diagrams. It's not perfectly convincing to me. Or at least it is not clear to me in the following details of the process:
...
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399
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Can we trap a light ray in a prism (in geometric optics)?
In geometric optics, light rays can enter a (finite) prism of constant refractive index, and bounce off the edges as long as the incident angle is less than the critical angle of the medium.
Is there ...
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Change in nature of image: Putting a concave mirror in water vs in air
I was wondering if we put a concave mirror in water, what will be the difference in the image formed by it in air vs water?
Exception: Here I mean except when rays come from infinity (e.g., sun) ...
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0
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What causes the distortion of an image when seen through a water droplet?
I'm trying to explain what causes an image to be distorted when seen through a water droplet.
Specifically, my example is that of a drop of water on a car window. We can see that the image is reversed,...
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Fermat's principle and a non-physical conclusion
Fermat's Principle is the statement that a ray will follow a minimum-time path between a point, A, to a point, B.
So, if I have a block of material of high refractive index, so that it slows the light ...
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Ambiguity in proof of angle of minimum deviation of for a prism [closed]
I have stumbled upon a proof from one of my friends that for a prism, the angle of minimum deviation is that in which incident angle is equal to emergent angle. i.e.
$$\delta = i + e - A$$
where $A$ = ...
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Optics question: Simple way to transform a parallel bundle of collimated beamlets into a converging (diverging) bundle of collimated beamlets?
I'm searching for an optical element that converts a parallel bundle of individually collimated beamlets into a converging or diverging bundle of still collimated beamlets (or vice versa). So ...
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1
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Could we appreciate Newton ring effects on a computer screen when pressing it?
This may sound like a pretty dumb question, but I've just found out about Newton rings and I wanted to know if the pattern of colourful circles observed in computer screens (especially old ones) when ...
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Analysis of the reflection in metal
In order to solve the reflexion in a material with a complex index the solution I've found on textbooks is to define $\hat{n}\cos{\phi}:=a+bi$ where $\hat{n}=n_r+n_ii$ is the complex index and then ...
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Hyperbolic lens shape and aspheric surfaces
In Optics, Hecht, the author states that the perfect surface for a lens shape will be a hyperbola.
He essentially derives this answer by writing the optical path length from F1 to A, then A to D, and ...
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128
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How to obtain the refractive index of a thin film via reflection?
I have analysed a thin-film sample on a reflective setup, using a setup similar to the one represented in the figure below. I also know the thickness of the sample d to be considerably smaller than ...
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How distant is the horizon on Venus?
Strong atmospheric refraction can make the horizon on Venus much closer than expected, but how close is it? My naive calculation is very different from reported observations.
A source cited in How ...
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Is it true to say no refraction takes place when a ray comes along normal drawn to interface?
Many books and websites in our country say that there are two conditions for no refraction of light:
If index of Refraction of media on both sides is same.
If the ray of light falls normally on the ...
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How to find the index of refraction of a glass cube with limited information?
This is a problem from my textbook that I've been struggling to solve:
A ray of light from a laser pointer is incident on the "upper" surface of a glass cube at the angle of 70°. The ray ...
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Thin layer of air between lenses in contact
consider the following case for thin lenses
Case 1: lens between two different medium
applying refraction through curved surfaces two times and subtracting -
$$\frac{\mu_{oil}}v - \frac{\mu_{air}}u = ...
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What exactly is "dense" in Optical Density?
My book states that:
When passing from one medium to another, if light slows down, the second medium is said to be optically denser than the first medium, and if light speeds up, then the second ...
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453
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Image Formation at a Spherical Refracting Surface
I was thinking about refraction at spherical refracting surfaces and what the required conditions be for the formation of a real or virtual image?
I thought I could use this formula:
\begin{equation*}
...
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3
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How does a rainbow show all of its colours?
My question is tied closely to this one, asked a while back on the website. As far as my understanding goes, a rainbow is formed by sunlight undergoing two refractions and a reflection inside ...
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1
answer
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Finding Shift due to Refraction in Multiple Slabs when the object and viewer are in different medium [duplicate]
So, suppose we have three rectangular slabs each of varying refractive indices(R.I.) and thickness. We have a real point object to the left of the first slab and we have an observer to the right of ...
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2
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Can we tell on which side of a lens an image appears?
Suppose I look through a single, thin, converging lens at an object on the opposite side. Depending on where the object is placed, the lens will either produce a real image on the side of the lens ...
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Sign Convention in Ray Optics
While solving questions on Refraction due to 2 spherical surfaces the sign of the image formed after the first refraction (here at '$A$') depends whether the image formed is towards left or right side ...
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Geometric optics explanation of lateral (transverse) chromatic aberration
The majority of pictures explaining lateral(transverse) chromatic aberration look like this
Here the focal point for red light is shifted closer to the optical axis and the focal point for blue light ...
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3
answers
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How does the combination of lens create a sharper image?
There's a line in a book which states that the combination of lens helps create a sharper image, but I don't understand how. Does more magnification mean sharper image?
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Rainbow reflections from salt crystals
Especially on a sunny day in the winter or spring, I often notice faint rainbows when I look down at the edge of the road by the curb. I am not sure what causes these rainbows, but I believe that ...
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Prism deviation angle for small angles
Consider the following scheme for monochromatic light refracting through a prism, with the deviation angle $\delta$:
Let $\theta_1\ \wedge\ \alpha\ll1$ . ...
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