All Questions
Tagged with optics thermal-radiation
13
questions with no upvoted or accepted answers
3
votes
0
answers
220
views
Kirchhoff's law for glass and transparent crystals; how exactly do hot transparent materials produce so much visible thermal radiation?
Together, the current answers to Is the visible light spectrum from "red-hot glass" at least close to Blackbody Radiation? explain that while we can not necessarily call a heated sample of ...
- 6,273
3
votes
0
answers
110
views
A problem concerning the change of temperature and spectrum of a filament
The spectrum of a filament has been given before, the left one having the lowest temperature, the middle with a medium temperature and the right one with the highest. My question is this: Why does the ...
- 165
2
votes
0
answers
34
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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
2
votes
0
answers
53
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Planck on the entropy of light
While reminiscing of his discovery of the quantum of action Planck writes in his "Scientific Autobiography" [1]:
Thus the nature of entropy as a measure of probability, in the sense ...
- 19.8k
1
vote
0
answers
37
views
How to measure light intensity in a room?
Does anyone know how I would go about measuring the light intensity in a room? I'm not interested in knowing the lux reading, I would like to measure the $W/m^2$ due to thermal radiation in my ...
- 31
1
vote
0
answers
70
views
Focusing blackbody light simulation
As an honest citizen, I do not intend to violate the laws of thermodynamics by concentrating the light emitted by a blackbody on a smaller area. However by playing with this wonderful 2d ray online ...
- 11
1
vote
1
answer
57
views
What could be and how to come up with a mathematical formula for the local electric field inside a blackbody cavity?
I asked a similar question here more than two years ago. I did not get an answer to my complete satisfaction. I would like to reiterate the problem again.
The local electric field of a monochromatic ...
- 26.8k
1
vote
0
answers
98
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probability of emission vs absorption in thermal radiation
I am trying to make sense of the thermal radiation emitted by a gas.
The radiative transfer equation is $$\frac{dI}{dx} = \epsilon - \kappa I,$$ where I is the intensity, $\epsilon$ is the ...
- 323
0
votes
0
answers
23
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Any research or study that monitored the spectrum of the natural light during the entire day?
I am interested in understanding the light spectrum during sunrise, morning, midday, afternoon, golden hour, and blue hour.
Is there anyplace I can look at those?
0
votes
0
answers
44
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Need clarity behind the theory of diffraction for a black-body source
Attempting to model the diffraction for a black-body source, I have stumbled upon a bit of a conundrum with the mathematics. I am not asking WHY the light is diffracted, but instead looking for a ...
- 553
0
votes
0
answers
22
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How to add markers to IR photographs
I'm using an IR camera to identify thermal patterns.
The thermal images are similar to this [LINK] image.
I'd like to add markers to the area being measured to determine dimensions and normalize the ...
- 111
0
votes
0
answers
22
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How does incandescent lamp mounting influence color temperature?
I have a high power incandescent halogen lamp, which I want to mount behind a pane of glass some distance away, such as to minimize that funky burning dust smell, that I really dislike.
Now say this ...
-1
votes
1
answer
42
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How many degrees Celsius/Fahrenheit can be reached in 1 square meter area using magnifying glasses?
The magnifying glasses are each 10 meters in diameter, their collected light is concentrated via mirrors into a 1 square meter spot. Is it possible to get a temperature higher than 2000 degrees ...
