All Questions
Tagged with refraction optics
916
questions
89
votes
9
answers
15k
views
What really causes light/photons to appear slower in media?
I know that if we solve the Maxwell equation, we will end up with the phase velocity of light being related to the permeability and the permittivity of the material. But this is not what I'm ...
- 2,452
59
votes
7
answers
10k
views
Could a human beat light in a footrace?
Is there anything preventing the following experiment from being done right now?
Imagine that a human ran from point 'a' to point 'b' while light
particles that reflected off a clock moved ...
- 1,315
52
votes
3
answers
21k
views
How does light speed up after coming out of a glass slab?
As I learned today in school, my teacher told me that when light enters a glass slab it slows down due to the change in density and it speeds up as it goes out of the glass slab. This causes a lateral ...
- 841
51
votes
2
answers
32k
views
Why do I see better under water using swimming goggles? [duplicate]
I am myopic (I don't really know if this is relevant or not) and I usually swim without contact lenses. My vision is clearly better underwater when I am using swimming goggles.
I have tried to ...
- 1,563
50
votes
3
answers
12k
views
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'...
- 13.5k
49
votes
5
answers
13k
views
If a lens focuses all incoming light to a point, how do we get 2D images?
How do lenses produce 2-dimensional images, if a lens bends all incoming rays of light to intersect at the focal point? Shouldn't this produce a single dot of light on a screen placed at the focal ...
- 601
45
votes
4
answers
4k
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How does Fermat's principle make light choose a straight path over a short path?
This is a thought experiment where I have made a "C" shaped hole inside diamond. The refractive index $(\mu)$ of diamond is 2.45. Say we shine a laser from top of the "C" as shown.
...
- 2,000
44
votes
4
answers
277k
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Virtual vs Real image
I'm doing magnification and lens in class currently, and I really don't get why virtual and real images are called what they are.
A virtual image occurs the object is less than the focal length of ...
- 6,927
36
votes
4
answers
5k
views
Why are the edges of a broken glass almost opaque?
Unfortunately I broke my specs today which I used in this question.
But I observed that the edges are completely different then the entire part of the lens. The middle portion of the lens was ...
- 8,230
33
votes
3
answers
3k
views
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 ...
- 1,064
27
votes
5
answers
16k
views
Eyes open under water
Yesterday I looked underwater with my eyes open (and no goggles) and I realized I can't see anything clearly. Everything looks very, very blurry. My guess is that the eye needs direct contact with air ...
- 3,930
26
votes
5
answers
176k
views
Why does the road look like it's wet on hot days?
Often, I'll be driving down the road on a summer day, and as I look ahead toward the horizon, I notice that the road looks like there's a puddle of water on it, or that it was somehow wet. Of course, ...
- 3,439
25
votes
3
answers
9k
views
Why doesn’t a normal window produce an apparent rainbow?
When light refracts in a prism it creates a rainbow. My question is, why don’t all windows or transparent objects create this dispersion, i.e. why is the refractive index dependent on frequency in a ...
- 969
25
votes
3
answers
4k
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Can air make shadows?
I have read about schlieren photography, which uses the ability of non-uniform air to create shadows. Is it really possible that air makes shadows?
user195448
24
votes
1
answer
27k
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How does a photon travel through glass?
This was discussed in an answer to a related question but I think that it deserves a separate and, hopefully, more clear answer.
Consider a single photon ($\lambda$=532 nm) traveling through a plate ...
- 4,700