All Questions
Tagged with optics thermal-radiation
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Radiation energy and momentum relation [duplicate]
Why is $\rho = 3p$ for radiation? What is the intuition behind this? If we had only 2 spatial dimentions, would it be $\rho = 2p$?
(I came across this relation while studying the state of the universe,...
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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 ...
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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?
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Breit–Wheeler γ γ′ → e+ e− pair production with hohlaraum as photon target; is this particular experiment going to be carried out?
The IFLScience article Scientists Work Out How To Make Matter From Light describes photon-photon collisions producing pairs of particles, and the Nature Photonics Letter A photon–photon collider in a ...
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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 ...
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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 ...
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Power received close to a large black body radiator
I am interested in calculating the power received by an object near a black body radiator. Say, for example, I had a piece of paper perpendicular to the earth's surface normal. If I make assumptions ...
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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 ...
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Photon statistics for thermal light?
I know that the variance $\Delta^2$ of the number of photons $n$ for thermal light is:
$\Delta^2 n = \bar{n} + \bar{n}^2 \hspace{2 cm} (1) $
where $\bar{n}$ is the average number of photons.
This ...
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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 ...
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What would a piece of high emissivity polished metal inside a blackbody cavity look like? Darker than the walls of the cavity but the same color?
I'm trying to work out the challenges to using an infrared pyrometer to measure the temperature of a piece of shiny metal. This device has no user-accessible emissivity setting, and my sample will ...
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What will happen if the inner walls of the perfect blackbody (shown in the image) is made perfectly reflecting?
I am curious about making the inner walls of this blackbody perfectly reflecting instead of perfectly absorbing.
If I keep on giving in incident radiation,the photon density inside will increase, ...
- 207k
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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 ...
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Why does cooling down thermal imaging cameras increase sensitivity?
A lot of high-sensitivity thermal cameras and sensors are (cryogenically) cooled down to low temperatures to achieve these high sensitivities. For example. the Stinger missile, and the James Webb ...
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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 ...
