All Questions
5,195 questions
3
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0
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141
views
What creates the orange hue when there is wildfire smoke?
I find a variety of opposing arguments on the internet:
That this is due to Rayleigh scattering, which "removes" the blue light from reaching our eyes. This is similar to how the sunset ...
- 131
2
votes
2
answers
308
views
How is it possible to form image of a virtual object (by reflection) if the rays do not diverge from a single point?
I was reading geometric optics when I came across the concept of virtual objects. I found the concept counter-intuitive, as far as reflection goes. (I perfectly understand the formation of such an ...
- 1,096
2
votes
3
answers
685
views
Young's double slit experiment with two wavelengths of light
I know that a double-slit experiment pattern for blue, and red light individually gives the intensity patterns easily found in textbooks. But I fail to understand the exact pattern produced by a ...
- 413
0
votes
2
answers
80
views
Photos don't feel as "green" as they look to the eye [closed]
During a cycling trip yesterday, I took photos of plants I saw along the way with my phone (which is a Samsung Galaxy A21s), and observed that the green colour was significantly more "brownish&...
- 926
1
vote
0
answers
40
views
Calculating non-dielectric reflectance without using complex numbers [closed]
I need a to calculate the fresnel reflection ratio of a non dielectric material given the incident angle, the refractive indexes of the incident and interfacing materials and the extinction ...
1
vote
1
answer
37
views
Why can a material mixture block all light?
Dyes and different colorings are often mixed into materials. These are usually a small fraction of the total material volume/mass and aren't painted on so don't have a uniform surface coat but some ...
- 982
0
votes
2
answers
216
views
Is the intensity of a light wave related to frequency of the wave?
My problem is: How can I resolve these following ideas?
Energy of photons in an EM wave is proportional to the frequency of the wave
Intensity of an EM wave is proportional to the energy that is ...
- 15
0
votes
2
answers
85
views
What happens when visible light transitions to invisible light?
I was just wondering what happens when you see a visible light, for example violet, and that light slowly increases/decreases until it's not visible to the human eye. Will it fade or just become ...
0
votes
0
answers
36
views
Has the speed of light always been constant? [duplicate]
Is there any evidence to suggest that the speed of light (or its other properties) has been unchanged since the beginning?
The particular curiosity stems from the redshift observed in distant galaxies....
- 287
1
vote
0
answers
25
views
Why is the solar spectrum at the surface of the Earth strongest in the visible light range? [duplicate]
I watched a CrashCourse video saying that nuclear fusion of $\rm H$ to $\rm He$ in the sun radiates mostly gamma rays. Then why are the lights that come to Earth comprise mainly of IR & visible ...
- 191
0
votes
1
answer
69
views
Can we observe a more recent space?
The space we are viewing now is their distant past as their light has only reached our eye or telescope after travelling a long distance at the speed of light. However, for lights that are still on ...
2
votes
0
answers
40
views
Would slowing down a beam of light change its wavelength and frequency?
I confess that I have little knowledge of physics, so this kind of thing really often goes over my head. However, I did read somewhere that the speed of a beam of light is the product of its ...
- 21
0
votes
1
answer
37
views
SETI: Are there holes in the EM spectrum that are quiet enough to communicate at decently large distances?
So this is a variant of this other question.
I know stars are big, they radiate a lotta energy, they have spectral lines. But how dense are these spectral lines and is there a noise floor at ...
- 1,733
0
votes
0
answers
22
views
How does diffuse reflectance brightness varies with the line of sight?
Wikipedia asserts that
The rays represent luminous intensity, which varies according to Lambert's cosine law for an ideal diffuse reflector.
Describing this figure:
I understand this is a ...
- 71
0
votes
2
answers
96
views
Is it really just the electrons which decide the reflection from metals?
uh I'm curious again regarding the theories of reflection.
This is known that
Metals contain free electrons that absorb energy and vibrate when they
come in contact with light. Later, they release ...
- 123
1
vote
2
answers
848
views
How can a lens collimate an image instead of just a point of light?
For some extended context, this is how Heads Up Displays (HUDs) and Reflector Sights work:
However, as far as a I know, a lens will take collimated light and focus it to a very small point called the ...
- 13
8
votes
4
answers
1k
views
How can things around us have different colours if they have specific emission spectra?
Objects appear in different colours because they absorb some colours (wavelengths) and reflect or transmit other colours. The colours we see are the wavelengths that are reflected or transmitted.
As ...
- 1,096
2
votes
0
answers
34
views
How is the Kelvin temperature of a light source or an image is calculated?
I searched for it but couldn't find any answer for this.
For a light source is it simply the average of the full spectrum power?
And how do you compute it for an image? How can you tell the difference ...
- 223
0
votes
1
answer
99
views
Is electromagnetism simply a model? [closed]
Electrons have an e-field, and a moving e-field causes a b-field. These fields are defined in such a way that it makes calculating things like forces much simpler.
Is this just a model and there aren'...
- 13
0
votes
2
answers
93
views
Visibility on an alien world [closed]
I asked this over on Worldbuilding, and I was told it'd be best to try here instead:
First, I should probably mention that I'm really bad at mathematics.
I'm working on a scientifically plausible ...
- 109
1
vote
0
answers
41
views
Change of light from not visible to visible
Can light from infrared or UV change to visible light when it passes through some other material?
- 11
10
votes
3
answers
1k
views
Spectroscopy: Yellow vs Magenta
I have a knot about the "secondary" colours and its spectra.
So If I look the spectra of white light, I can see that yellow, which is between R and G, has some wavelength. If I do an ...
- 151
1
vote
1
answer
161
views
How do surfaces absorb and reflect light at the atomic level, and what does that have to do with color?
This is sort of a 2 part question that I'm really struggling to figure out.
When white light (which as far as I understand, is just a composition of most electromagnetic frequencies) bounces off, say,...
- 33
4
votes
2
answers
367
views
Can photons form a black hole?
Can photons form black holes the same way as other matter? If there happens to be enough of them concentrated in an area of space so that enough energy exists within a radius to form an event horizon, ...
- 143
0
votes
0
answers
124
views
Focus sunlight into a line and not just a point with lenses
Using a magnifying lens with the sun as the source, one can focus the light in a single point.
Is it possible to use just lenses, or any number of transparent materials of any particular shapes, to ...
0
votes
0
answers
50
views
Is it possible to have single-sided refraction?
Is it possible to have light refract in one direction, then reflect off a mirror but come back as a straight line like the picture below?
The context of this problem is in lens optics when a ...
- 1
0
votes
0
answers
22
views
Veracity of light field propagation simulation method (Combined Split-step Fourier and BPM)
When trying to simulate light propagation in three spatial dimensions and one temporal dimension I encountered a method given in this thesis. Here (on page 32), it is proposed to do a BPM within a ...
- 11
0
votes
1
answer
51
views
Precise Focal Length of a Concave Mirror
I have recently been working with concave mirrors, I was unable to understand why the focal length could be half the radius and later found out that it is only accurate for small apertures and angles ...
4
votes
1
answer
304
views
What causes the Faraday effect, on a material level?
I understand that the Faraday Effect is due to the velocity of propagation for left and right circularly polarized light being different in many optically-transparent dielectric media when exposed to ...
8
votes
2
answers
1k
views
Why do I see a rainbow when I look at Insulfilm with my sunglasses?
I'm wearing glasses with a sunglass clip-on. This means I have my regular glasses and, on top of them, I have a second pair of lenses that work as sunglasses and attach to my regular glasses using ...
- 23k
0
votes
2
answers
209
views
Why does light (supposedly) move diagonally in Michelson-Morley Experiment? [closed]
(Im specifically referring to this video at 12:30)
In Michelson-Morley experiment, one light beam goes perpendicular to the velocity of earth, and other goes parallel to the velocity of earth.
Im ...
- 1,306
0
votes
0
answers
48
views
What is the optical (and possibly physiological) explanation behind the additive mixing of separate colour dots as used in printing?
Industrial printing is based on autotypical colour mixing, the simultaneous effect of subtractive and additive colour mixing. This makes it possible to render a large set of colours using only four ...
- 101
1
vote
7
answers
569
views
What is the waveform of white light?
I don't know very much about the theory of light, but since people talk about light as a wave and talk about the wavelengths of light, I'm going to assume that whenever you see any source of visible ...
- 2,069
-3
votes
1
answer
45
views
Is this Article misleading about the diffraction part? [closed]
The following article states that because of the diffraction, the egg is visible, I don't think that's correct, because diffraction occurs at every edge that light passes but it will just slightly ...
2
votes
2
answers
271
views
Difference between white and reflective objects?
A White object reflects all the visible colored light but so does a flat silver object (mirror) so what makes them look so different?
This has been answered here but that shouldn't be true because ...
- 123
0
votes
0
answers
80
views
Can a mote of dust create a rainbow/prism like effect if floating inside the light of a sunbeam and seen from the right angle and/or device?
The device could be a telescope, microscope, camera, or anything that zooms in with great clarity. I'm pretty sure that lots of dust together in one place in a sunbeam can have this effect (please ...
1
vote
1
answer
119
views
Why does redshift happen?
If an object B does NOT move away from us, doesn't matter whether it's 10 km or 5,000,000 km away from us, I think redshift wouldn't happen.
Now, if the object is moving away from us, it's said that ...
- 397
21
votes
8
answers
6k
views
Why don't objects get brighter when I reflect their light back at them?
In a well-lit room, a light source shines light on the objects in the room, some of which reflects back off the objects. We can make the light source brighter by causing it to emit more photons, which ...
- 1,277
0
votes
0
answers
24
views
Does time slow down for light according to relativity? [duplicate]
According to Einstein's theory of relativity
Time slows for a individual who moves at the speed of light and time goes backward if the individual is faster than the speed of light.
So , is it that for ...
- 735
2
votes
2
answers
320
views
Why does light either get reflected, absorbed, or passes through a surface or obstacle?
For each of these 3 cases, I'm having trouble understanding...
If light is reflected, does that mean that there was not sufficient energy by the photons to excite the electrons of the surface to ...
- 195
0
votes
2
answers
224
views
Does the light from my flashlight travel into space? [duplicate]
Does the light from my flashlight travel into space?
1
vote
1
answer
120
views
Lorentz force in Zeeman effect
I’m reading Zeemans 1897 paper on his discoveries of line splitting.
https://articles.adsabs.harvard.edu/full/1897ApJ.....5..332Z
He cited Lorentz who says that a circular rotating “ion” ( electron ...
- 49
4
votes
1
answer
2k
views
How does the flickering flame light bulb work?
I bought this "flickering flame bulb" recently.
This is what it looks like:
https://www.youtube.com/shorts/Py7pD0Oor9o
Here is the same thing but in slightly slow motion:
https://www.youtube....
- 153
1
vote
1
answer
38
views
Should blue & white stars appear red and inflated while observed on the lower part of the night sky for the similar reason as the Sun during sunset?
Should blue and white stars appear red and inflated while observed on the lower part of the night sky for the fairly same reason as the sunlight during sunset? As these stars emit blue light ...
- 2,275
0
votes
2
answers
285
views
Difference between white and yellow light bulbs
Whats the difference between the white light bulbs and yellowish tinted light bulbs what makes the color yellowish? Do they both emit multiple wavelengths of all the colors or does one of them emit ...
- 17
1
vote
1
answer
426
views
How does light interact with atoms? [closed]
I've read this answer regarding the difference between mere reflection and absorption followed by emission and I am struggling to understand some concepts. To begin with, we have some matter-light ...
- 11
18
votes
5
answers
4k
views
How do telescopes see many billion light years distant object in our universe?
How do telescopes see many billion light years distant object in our universe?
As an individual with limited expertise in the field of astronomy, my current understanding suggests that the observation ...
2
votes
1
answer
229
views
If light bends twice as much as Newton predicted, does it fall faster than other things?
We know that through GR, in a gravitational field light bends twice as much as predicted by strict Newtonian physics. In researching this I've found explanations like light bends on both the space ...
- 4,849
0
votes
1
answer
62
views
Why are shadows translucent?
Just saw a video about how the shadow on moon is pitch black.
That took me to the question of scattering. I have myself asked a question similar to this already.
When light from a bulb(consisting of ...
- 1,306
1
vote
1
answer
514
views
Deriving the focal length of a graded index lens (GRIN)
I want to find a closed expression of the focal length of a graded index since I don't manage to find any on the internet. I already checked this out: Determining the focal length of a gradient index ...
- 334