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1answer
51 views

Why does glass absorb infrared light?

I was under the impression that glass was transparent to light with a wavelength above ultraviolet, but when playing with my latest toy, an infrared thermometer which brought up a question I asked ...
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2answers
932 views

Why does my infrared thermometer say the sky is at -2 °C?

I just got myself an infrared thermometer. I wouldn't have been able to predict what temperature it would give me when pointing at the sky, but it turned out to be -2 °C the first time I measured, and ...
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1answer
31 views

What does adding a visible light blocking IR filter do with heat?

Lets say I have a strong halogen light source which has a lot of IR radiation (e.g. a construction lamp). If I change the transparent front glass from the enclosure with a IR filter that blocks ...
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2answers
103 views

Can the hot combustion products from a large flame be in “non-local thermal equilibrium”

Question: Does it take some time for the hot combustion products from a flame to reach local thermodynamical equilibrium (i.e. for the energy state populations to follow the Boltzmann distribution)? ...
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1answer
21 views

Rate of radiation of infra-red ray from a hot body?

I have the equation $\frac{dE}{dt}=a(\tau^4-\tau_s^4)$ however I can't find anywhere what E is supposed to be. It is not pointed out anywhere in the text and what is confusing is that in engineering E ...
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2answers
60 views

How camera flash can send information

Nikon have CLS a system that allow to trigger one flash with other flash. I don't know how exactly it work from user point of view, I think that one flash (in command mode) can send information like ...
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0answers
20 views

Transmissivity of Liquid Crystals in the near-infrared range

The gist of my query is in the title. I have been searching for papers and studies that could provide transmission curves (in nematic liquid crystals) across the visible to near-IR range (or from ...
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3answers
1k views

Why does a human body only emit infra red radiation and not other types of electromagnetic radiation?

What causes humans to emit infra red radiation and why don't we also emit other types of electromagnetic radiation such as ultra violet or microwave? Sunlight contains UV and our body takes it in, but ...
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0answers
16 views

What is the amount of EM energy from the sun reaching the earth as a function of wavelength?

The question stems from a desire to know if more light from the sun in the infrared wavelengths has more energy than light at say yellow or violet wavelengths - at the Earth's surface. I'm guessing a ...
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1answer
67 views

Thermographic camera vs infrared camera

AFAIK, all objects above 0K emit infrared radiation. It is an electromagnetic radiation, like visible light. I guess thermographic and infrared cameras work on the same principles, but their images ...
0
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2answers
161 views

How to test cutoff frequency of IR filter on camera?

Modern cell phones seems to come with IR filters on their cameras. I want to do an experiment to figure out what wavelengths these filters allow to pass and which they block. How would I go about ...
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2answers
321 views

Incorrect IR temperature reading on stainless steel?

Using a Fluke 62 Mini Infrared Thermometer today on a stainless steel pipe with coolant I noticed that it gives incorrect temperature readings. There is a temperature sensor inside the coolant ...
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4answers
391 views

How does Infrared Relate to heat?

I never understood the relationship between Infrared and Heat. Is IR emitted when heat is generated, is heat generated when IR is made, and how do the two relate?
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2answers
554 views

Why do moving particles emit thermal radiation?

While answering another question about heat in an atom, the discussion in the comments led to the question of how heat is related to thermal radiation picked up by infrared cameras. The answer is that ...
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0answers
75 views

Why is infrared imagery of Mars' surface sharper / richer in contrast than that from the visible spectrum?

Looking at the terrain of Mars through Google Mars, it seems to me that the infrared imagery is much crisper, the images from the visible spectrum seem to be somewhat hazy. I'm wondering if that is ...
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1answer
298 views

Composition of solar spectrum

I read some where that there are three types of UV and infrared rays namely UV-A, UV-B, UV-C and near infrared, mid infrared and far infrared. Which is the most abundant among the the three in ...
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2answers
365 views

What's the Significance of Color Changes Between EM-Spectrums?

As everybody knows that Black objects are black because almost all the light that falls on them is absorbed into the material. Little or no light is reflected back toward our eyes, therefore we see ...
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1answer
117 views

william herschel discovering infrared problem

when william herschel conducted the experiment of separating white light with a prism and measuring the different colors, he put a thermometer past the red color as a control finding it to pick up the ...
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1answer
514 views

Can infrared light be sent to long distance?

I need to send infrared light from its emitter to a distance of about 10-12 feet. Is this possible?
2
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1answer
142 views

Commercial Infrared lights

I purchased an infrared light. It's a 100 W Philips infrared lightbulb. Says it's infrared, but I haven't done any spectrum analysis so I don't know for sure if it's just red or really infrared. As I ...
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3answers
734 views

What's the physical difference between a convective heater and an infrared heater?

Could someone please explain why there are 2 types of space heaters-- one that is convective and one that is infrared? Why does the first one not radiate and why does the second one not heat the air? ...
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4answers
462 views

Is infrared light diffused on walls?

Lamps that produce visible light can light up a whole room because the ceiling and the walls diffuse light. This way, when there is a single lamp in a room, something that is in the shadows is not ...
3
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2answers
65 views

Particular targets of high angular resolution infrared telescopes

I work in the field of infrared interferometry, specifically instrumentation. As such, I need to be aware of the science goals of such an instrument. Is there a quick list of important and ...
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1answer
2k views

How does the aluminium foil do the thermal and WiFi isolation?

Aluminium foil is widely used for thermal isolation. As far as I know it reflects the thermal infrared radiation. Also I've seen a lot of guides about strengthening WiFi signal by putting the ...
4
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1answer
1k views

Why does an infrared thermometer display very low temperature when being directed to the outer air?

I'm toying with an infrared thermometer - one which you point onto an object, press the button and it instantly measures the temperature by estimating the infrared radiation from the object. It shows ...
0
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1answer
89 views

Does every wavenumber of IR result in a different kind of vibration?

Does every wavenumber of IR result in a different kind of vibration? If that is true, what if a molecule absorb 2 different wavenumbers (which cause different rocking and symmetrical stretching for ...
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1answer
419 views

Are silicone polymers transparent to infrared light?

I know that silicon and even black plastic bags are transparent to infrared light. What about light-colored silicone polymers (take white or green colors)? Are they transparent to infrared light too? ...