All Questions
Tagged with optics visible-light
197
questions
116
votes
6
answers
115k
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Why is glass transparent?
Once I asked this question from my teacher and he replied "Because it passes light.". "And why does it pass light?" I asked and he said, "Because it is transparent.".
The same question again, Why ...
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52
votes
3
answers
21k
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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
121
votes
7
answers
62k
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Why are most metals gray/silver?
Why do most metals (iron, tin, aluminum, lead, zinc, tungsten, nickel, etc.) appear silver or gray?
What makes copper and gold have different colors?
What atomic characteristics determine the color?
- 1,829
17
votes
2
answers
10k
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What is Gray, from a physics POV?
Quora explains how white and black colors fit into the spectrum of visible light. It explains that white is all colors together while black is the lack of color.
So, where is Gray? Gray is the mix of ...
- 2,918
50
votes
5
answers
15k
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Why does the sky change color? Why is the sky blue during the day, red during sunrise/set and black during the night?
Why does the sky change color? Why is the sky blue during the day, red during sunrise/set and black during the night?
user68
29
votes
1
answer
7k
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How are photons "consumed"?
I have very little background in physics, so I apologize if this question is painfully naive.
Consider the following thought experiment: an observer is in a closed room whose walls, floor, and ...
- 493
68
votes
6
answers
15k
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How does light combine to make new colours?
In computer science, we reference colours using the RGB system and TVs have pixels which consist of groups of red, green and blue lines which turn on and off to create colours.
But how does this work?...
- 1,945
41
votes
2
answers
18k
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Why is the sun brighter in Australia compared to parts of Asia?
Background:
I've lived in Philippines for several years, and visited other parts of Asia occasionally (Singapore, Indonesia, Hongkong).
I just moved to Western Australia a few months ago and I ...
- 863
27
votes
9
answers
8k
views
What determines whether colors you can't see are visible or not?
So, when someone is red-green colorblind, the colors appear the same to them, like this:
Source: https://iristech.co/what-do-colorblind-people-see/
And if you're totally colorblind, then things ...
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22
votes
5
answers
2k
views
What longest time ever was achieved at holding light in a closed volume?
For what longest possible time it was possible to hold light in a closed volume with mirrored walls?
I would be most interested for results with empty volume but results with solid-state volume may ...
- 11.2k
180
votes
7
answers
14k
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Why do we actually see the sun?
I haven't yet gotten a good answer to this: If you have two rays of light of the same wavelength and polarization (just to make it simple for now, but it easily generalizes to any range and all ...
user22862
17
votes
2
answers
3k
views
If light rays obey to the wave equation, why can they be thought as straight lines?
I'm a newbie with physics but I'm wondering how a ray of light can essentially be represented. I have always known that a ray of light proceeds in a straight line until it encounters another object (...
- 281
11
votes
1
answer
1k
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If refraction slows down light, isn't it possible to hold light still?
I have a quick question about the refraction of light, and I'm sorry if it seems a bit simplistic or even stupid, but I'm still learning.
We know that when light passes through a denser medium, it ...
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510
votes
6
answers
81k
views
How does light bend around my finger tip?
When I close one eye and put the tip of my finger near my open eye, it seems as if the light from the background image bends around my finger slightly, warping the image near the edges of my blurry ...
- 4,859
68
votes
12
answers
34k
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Is it possible that there is a color our human eye can't see?
Is it possible that there's a color that our eye couldn't see? Like all of us are color blind to it.
If there is, is it possible to detect/identify it?
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