All Questions
Tagged with electromagnetic-radiation optics
712
questions
311
votes
2
answers
30k
views
What is Chirped Pulse Amplification, and why is it important enough to warrant a Nobel Prize?
The 2018 Nobel Prize in Physics was awarded recently, with half going to Arthur Ashkin for his work on optical tweezers and half going to Gérard Mourou and Donna Strickland for developing a technique ...
- 134k
156
votes
1
answer
15k
views
What is an "attosecond pulse", and what can you use it for?
The 2023 Nobel Prize in Physics was announced today, and it was awarded to Pierre Agostini, Ferenc Krausz and Anne L’Huillier, for
“experimental methods that generate attosecond pulses of light for ...
- 134k
116
votes
6
answers
115k
views
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 ...
- 5,377
84
votes
3
answers
10k
views
Can photons be detected without being absorbed?
I am thinking about a detector that would beep if light passes through it. Is it possible?
- 841
70
votes
6
answers
12k
views
Why isn't my calculation that we should be able to see the sun well beyond the observable universe valid?
I recently read an interesting article that states that a human being can perceive a flash of as few as 5 or so photons, and the human eye itself can perceive even a single photon. The brain will ...
- 691
49
votes
8
answers
14k
views
How is it possible there are UV photos while our eyes cannot detect UV waves?
I know this question sounds dumb, but please bear with me. This question came into my mind while I was looking at the photos in an astronomy book. How is it possible that IR and UV photos of stars and ...
- 761
45
votes
6
answers
10k
views
Does pure yellow exist in variations we can't discern? [duplicate]
If you add red light (~440 THz) and green light (~560 THz), you get what we perceive as yellow light (~520 THz). But I assume what you really get is a mixed waveform that we perceive as yellow? ...
- 579
45
votes
3
answers
29k
views
How do Optically Active Compounds Rotate Plane Polarized Light?
I am not sure if this is more of a Chemistry or a Physics question, but in my Organic Chem class we discussed that chiral molecules will rotate plane polarized light. However, my professor did not ...
- 451
42
votes
3
answers
11k
views
Why does a mirror reflect visible light but not gamma rays?
Visible light (~500 THz) as well as gamma rays (~100 EHz) are electromagnetic radiation but we can reflect visible light using a glass mirror but not gamma rays. Why is that?
- 551
41
votes
5
answers
13k
views
Can you bend light to go in a circle?
Is it possible to bend light so that it forms a circle and goes round and round indefinitely without losing energy?
- 2,005
36
votes
2
answers
4k
views
Should a superconductor act as a perfect mirror?
I have been told that metals are good reflectors because they are good conductors. Since an electric field in conductors cause the electrons to move until they cancel out the field, there really can'...
- 912
34
votes
4
answers
21k
views
Explain reflection laws at the atomic level
The "equal angles" law of refection on a flat mirror is a macroscopic phenomenon. To put it in anthropomorphic terms, how do individual photons know the orientation of the mirror so as to bounce off ...
- 697
29
votes
1
answer
5k
views
Why is UV light visible when reflected off paper?
I was carrying out a photoelectric effect experiment when I realised that the $365$ nm line in the mercury spectrum was surprisingly visible when shone onto a piece of paper. This lies in the UV ...
- 510
28
votes
5
answers
8k
views
Why does a pinhole create an image of the Sun?
When I was a kid I happened to encounter a solar eclipse. I was taught that I should not look at the Sun directly when it is undergoing an eclipse, but I was extremely curious to see it.
Somebody ...
- 2,517
24
votes
4
answers
8k
views
Why can't sunlight reach the very deep parts of an ocean?
Sunlight reaches the surface of the ocean and refracts. So it is still there. And its speed is about $225000$ km/s in water which is still incredibly fast. Light is a massless electromagnetic wave. So ...
- 402