All Questions
169
questions
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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 ...
- 284
2
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 ...
- 21
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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, ...
- 187
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votes
1
answer
45
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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 ...
- 187
1
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2
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72
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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 ...
- 101
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4
answers
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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 ...
- 51
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2
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75
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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 ...
- 187
2
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35
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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 ...
- 187
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68
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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 ...
2
votes
1
answer
201
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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 ...
- 23
1
vote
1
answer
71
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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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votes
1
answer
45
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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 ...
2
votes
2
answers
130
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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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66
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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 ...
- 252
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2
answers
53
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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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