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15
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2answers
1k 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 ...
8
votes
2answers
121 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)? ...
6
votes
1answer
2k 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 ...
6
votes
1answer
5k views

What common materials absorb most infrared light?

I'm competing in a simple robotics competition where most of the participants use reflected infrared light to detect their opponent. I'd like to make my own robot as difficult to see as possible. What ...
6
votes
2answers
2k 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 ...
5
votes
2answers
1k views

Why do we use microwaves in microwave oven?

We know that any object above absolute zero emits electromagnetic radiation. So hotter the object shorter the wavelengths. In the electromagnetic radiation spectrum radio waves has the longest then ...
5
votes
1answer
3k 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 ...
3
votes
3answers
731 views

Do infrared lamps provide more heat than incandescent lamps?

Infrared lamps seem to be used in situations where you want to produce heat without producing (as much) light. But incandescent bulbs also produce heat. Why not just use incandescent bulbs? My ...
3
votes
2answers
1k 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 ...
3
votes
1answer
157 views

Why infrared light waves is visible through camera? [duplicate]

For example We know that some television manufacturers have the limited IR-based remotes which cannot be seen by our eyes directly but while playing when I just put my camera in front of my TV remote ...
3
votes
1answer
72 views

Is it possible to improve the efficacy of light bulbs with a semipermeable mirror? (The greenhouse bulb)

Let us imagine that there exists a material that reflects infrared radiation, but is transparent for visible light. Could we take an incandescent bulb and add this material to the inner surface of the ...
3
votes
2answers
131 views

How does an infrared thermometer actually calculate temperature?

I am slightly confused about infrared radiation and the equations related to it. $P = A \epsilon \sigma T^4$ (1) and $B_{\lambda}(\lambda,T) = \frac{2hc^2}{\lambda^5} \frac{1}{e^{\frac{hc}{\lambda ...
3
votes
1answer
211 views

Using infrared temperature sensor to measure water surface temperature

Can I use infrared temperature sensor (such as TS118-3) to measure water surface temperature? I'm afraid some effects such as reflection of infrared waves from water surface and blinking because of ...
3
votes
2answers
68 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 ...
2
votes
5answers
5k 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?
2
votes
2answers
679 views

Why human and most of vertebrates cannot see Near-Infrared light (720nm-1500nm)? [closed]

On daytime, the surface of Earth is illuminated abundantly by light of spectrum from 250nm-1500nm, that includes near-ultraviolet spectrum (250nm-380nm), visible spectrum (380nm-720nm) and ...
2
votes
1answer
114 views

How long does it take plasma to radiate its heat?

Lets say we have 1 gram of plasma (Argon) at 1 million kelvin confined in a vacuum with electromagnets. If we keep the magnets on but shut down the device that heated the plasma, how long will it take ...
2
votes
1answer
2k 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 ...
2
votes
1answer
43 views

Explaining William Herschels Infrared Discovery

First post, and probably a very simple answer that I'm missing, but here goes. Herschel found that red light warmed a thermometer more than blue light, and consequently that the region beyond the red ...
2
votes
1answer
138 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 ...
2
votes
1answer
170 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 ...
2
votes
2answers
385 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 ...
2
votes
1answer
61 views

Short Laser pulse in near field bandwidth

Is there a way to create a short laser pulse that has, at least in the near field, a very narrow frequency range?
2
votes
1answer
139 views

What material would block (reflect, appear opaque) IR light 750-850nm range, but allow visible light to pass? [closed]

I'd like to find a material, ideally a plastic, that would prevent IR light from passing , but appear as transparent as possible to visible light. I've sampled some plascolite products and they work, ...
2
votes
2answers
72 views

Thermographic camera - show for visiting school children

Next week a group of pupils (12-14 years old) will visit my institute. I would like to teach them about infrared radiation. Do you have any suggestion what kind of simply and impressive experiments I ...
1
vote
4answers
10k 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 ...
1
vote
2answers
125 views

Does a source emitting visible light also emit infrared, microwave and radio waves?

I have a bulb which is hot enough to emit visible light and obviously it's hot enough to emit radiation which lies before the visible light temperature i.e. radio waves, microwaves, and infrared ...
1
vote
2answers
73 views

Is there a portable method of preventing all IR radiation from being emitted?

Me and some friends were recently disuccing "How cool it would be to be invisible", from a military viewpoint, I said that Camouflage, when done correctly, works surprisingly well, so invisibility was ...
1
vote
3answers
180 views

How damaging is light? [closed]

On Surely You're Joking Mr Feynman, when talking about the Trinity test, the author states: the only thing that could really hurt your eyes (bright light can never hurt your eyes) is ultraviolet ...
1
vote
1answer
106 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 ...
1
vote
1answer
212 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 ...
1
vote
3answers
2k 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? ...
1
vote
1answer
44 views

Why infrared absorption is a nonlinear technique?

I am looking for a good explanation and/or reference quotation explaining why infrared absorption technique is essentially nonlinear (eg. for carbon monoxide quantification). When using ...
1
vote
2answers
371 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 ...
1
vote
4answers
855 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 ...
1
vote
1answer
49 views

Can you use infra-red goggles (or similar principle) to see through mist and fog?

As per title really... fog is obviously quite opaque to visible light yet transparent to radio waves. What is the range of frequencies at which fog is opaque, and is either end of this range at a ...
1
vote
0answers
28 views

How can we detect the property of matter by using mechanical waves or IR or any other way

First of all, I am in high school[to tell that I don't know much physics]. And the second thing is that, I am not sure whether this question is specifically related to physics. What I want to ...
1
vote
0answers
78 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 ...
0
votes
1answer
49 views

Can infrared lasers still do damage to things if they are powerful enough?

So I get that infrared light is not visible to the human eye without some sort of device to assist in helping you see it, but I was just wondering how that plays into things like lasers. I know you ...
0
votes
1answer
124 views

Does sunlight contain 940nm wavelength light?

Apologies if this has an obvious answer, my knowledge of this area is very limited. I am attempting to produce a setup that will allow me to illuminate objects in 940nm wavelength infrared light, and ...
0
votes
1answer
28 views

How does the flow of photons (qty/s) vary across the spectrum? (In everyday life)

Humans see only a narrow band of light wavelengths. Many animals see much deeper into infrared. Maybe one clue to explain why we don't see IR naturally, has to do with the light intensity as a ...
0
votes
2answers
123 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 ...
0
votes
1answer
700 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 ...
0
votes
1answer
1k 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?
0
votes
1answer
796 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? ...
0
votes
0answers
19 views

Can near-infrared spectroscopy distinguish between various metals?

Can near-infrared spectroscopy be used to distinguish metals from another? If not, why not?
0
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0answers
15 views

Why would longer distance between collimated lenses improve coupling efficiency?

Im coupling 1550nm output from a single-mode lensed optical fiber to a standard SMF using a pair of collimating lenses, matched to the NA of the respective fibers. However, I find that by increasing ...
0
votes
0answers
14 views

Optimal wavelength for low IR attenuation under normal atmospheric conditions?

I can't find any good data about the transmit attenuation of infrared light in the atmosphere transmitted horizontally (there is a bunch of stuff detailing penetration of radiation from space, but ...
0
votes
0answers
33 views

What is source of Infrared Radiation from some solid object? [duplicate]

I use a Fluke infrared temperature measurement meter for various applications. I have not thought too much about the source of that infrared radiation until recently. Assume some solid with maybe a ...
0
votes
1answer
39 views

Can high-power LEDs remotely control a whole room? [closed]

Let's say I have 4 appliances in rectangular based room of about 60 square meters with white walls. The appliances are using infrared receivers with a filter of 38 kHz. Would it be possible to apply ...