All Questions
75
questions
2
votes
2
answers
83
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Is reflected photon the same? [duplicate]
When a single photon is reflected is the same one, or is it a new photon (emitted) while the 'original' photon has been absorbed?
I'm not sure how to imagine a refleced photon - it's not a ball ...
- 209
0
votes
2
answers
63
views
Which factors determines whether a photon is absorbed? [duplicate]
After some research, I figured out that all EM waves/photons are absorbed by atoms by exciting an electron from an orbital to an other. However, atoms emit only certain EM waves with specific ...
- 167
2
votes
3
answers
54
views
Density of photons in an expanding image?
This is a question from an interested amateur. Math welcome (as I or another may investigate it some day) but don't expect me to understand it in your answer.
Consider a star emitting light. In ...
- 21
1
vote
2
answers
140
views
How can photons be emitted from a star, travel millions/billions of years in a "straight line", and be seen by two adjacent observers?
If photons are emitted by a star and travel millions/billions of years in a "straight" line, they can be seen by adjacent observers. This makes it seem like there must be an uncountable ...
- 23
0
votes
3
answers
88
views
Where do the photons go in polarized filters?
If a pair of oppositely polarized (v/h) filters are put together, no light photons get through, so if all light photons incident on such a setup get reflected, the setup would
a) be a perfect mirror,
...
- 49
0
votes
0
answers
57
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How to interpret light and photon?
I've been trying to solidify my understanding on properties of light and this is what my understanding is so far:
Light is an EM wave that travels in a constant speed C.
Light has a quantized energy ...
- 275
1
vote
4
answers
87
views
Seeing trajectory of light
I had gone through a few posts on this topic in this community,however the doubt i have is different from them a bit. There it was said that we do not actually see a laser beam unless they are ...
- 1,179
0
votes
1
answer
47
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Does any colour appear white to our eyes if its emitted power is extremely large?
let's consider an ideal monocromatic source (for instance red) and let's assume you can regulate its emitted power without compromising its spectral "finesse".
Start from 0 emitted W/sr. It ...
- 1,319
0
votes
0
answers
57
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Clarifications about units of Photon Flux (PF) and Photon Flux Density (PFD)
I have an emitting source of light (this LED - Light Emitting Diode, UO variant).
On page 5 I read the minimum PF Photon Flux is ...
- 99
1
vote
1
answer
327
views
Does light intensity affect transparency?
The reason for the transparent nature of glass is that the photons of visible light don't have enough energy for the electrons of glass to absorb and jump to higher energy levels. As a result, the ...
- 19
3
votes
1
answer
204
views
Can there be a single ray of light?
My physics teacher told me that a beam of light is a collection of rays of light and there cannot be a single absolute ray of light. Is this true?
30
votes
10
answers
8k
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If light propagates like waves, why can't I see around corners?
I know two different descriptions of how light propagates in space; (1) like particles traveling and reflecting in straight lines. And (2) like waves spreading and interfering in space. And that both ...
- 1,153
0
votes
0
answers
30
views
Does the interaction between 2 photons change its traveling directions?
As I understand from the Hong-Ou-Mandle effect, the interaction between 2 photons is possible. Can 2 Photons interact with each other in free space? Suppose that the 2 photons met in the spacetime ...
- 81
11
votes
4
answers
3k
views
If a polarized light wave is indistinguishable from its original self after being flipped 180°, why doesn't a photon have a spin of two?
The spin of a photon has a counterpart in classical physics, it's polarization, right?
And if you spin a polarized light wave by 180°, (or pi radians), it is now the same as before, correct?
So why ...
- 4,509
0
votes
1
answer
32
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What's the track it will be for light?
Let's suppose one shaking light starts from Proxima Centauri and travels toward the earth. We know light will travel from more 4 years to reach the earth. It will be interesting if we 'look' at the ...
- 23