What is Infra red: Definition and 14 Discussions

Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from the nominal red edge of the visible spectrum around 700 nanometers (frequency 430 THz), to 1 millimeter (300 GHz) (although the longer IR wavelengths are often designated rather as terahertz radiation). Black-body radiation from objects near room temperature is almost all at infrared wavelengths. As a form of electromagnetic radiation, IR propagates energy and momentum, with properties corresponding to both those of a wave and of a particle, the photon.
Infrared radiation was discovered in 1800 by astronomer Sir William Herschel, who discovered a type of invisible radiation in the spectrum lower in energy than red light, by means of its effect on a thermometer. Slightly more than half of the total energy from the Sun was eventually found to arrive on Earth in the form of infrared. The balance between absorbed and emitted infrared radiation has a critical effect on Earth's climate.
Infrared radiation is emitted or absorbed by molecules when they change their rotational-vibrational movements. It excites vibrational modes in a molecule through a change in the dipole moment, making it a useful frequency range for study of these energy states for molecules of the proper symmetry. Infrared spectroscopy examines absorption and transmission of photons in the infrared range.Infrared radiation is used in industrial, scientific, military, commercial, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space such as molecular clouds, to detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect the overheating of electrical components.Military and civilian applications include target acquisition, surveillance, night vision, homing, and tracking. Humans at normal body temperature radiate chiefly at wavelengths around 10 μm (micrometers). Non-military uses include thermal efficiency analysis, environmental monitoring, industrial facility inspections, detection of grow-ops, remote temperature sensing, short-range wireless communication, spectroscopy, and weather forecasting.

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  1. Nima_khademi

    Calculating a distributed IR source radiant flux

    Hello everyone! does anybody know How can I calculate a distributed radiant flux of an IR source in a space? Is there any software or something?
  2. A

    B What easily avaible liquids are transparent in IR?

    Hi I want to make a infrared nonimaging concentrator, but since crystals needed for lenses are difficult to work with for an amateur, want to use liquids. I am interested in the 1-12 micron spectrum; what liquids could i use?
  3. J

    Materials that allow IR or UV light to pass through?

    Glass allows visible light to pass through I would like to find a list of materials that allows lights of different EM spectrum to pass through, not just the above, Searched throughout google, couldn't find any!.
  4. oversight

    How do I measure the temperature of my infrared sauna?

    Sooooo... I have a Far infrared (FIR) sauna. It has large flat 'carbon' panel heaters. They get warm to the touch and won't burn you if you touch them. My non contact infrared thermometer zapper says that they get to about 70 degrees C. They are meant to be producing lots of FIR. A regular...
  5. H

    Infra red and ultra violet vision

    I heard that snakes can see infra red waves and e.g. bees can see ultra violet light. so... infra red = heat = snakes have heat vision? and do bees see ultra violet as a color? if yes, does it mix with other colors or is it like a filter?
  6. M

    Infra red transceiver questions

    Hi, I need circuits for an infrared transmitter and receiver. i need to use 38 kHz square pulse please guide me as early as possible...
  7. V

    Create a beam of infra red

    the name says everything...but i want to know which metal is the besst to create infrared frequency and how far can it travel,bounce n come back with a detectable intensity? i know the 2nd question is stupid coz we r talking abt em wave they don't get absorbed in medium but they do get...
  8. J

    Infra Red Emittor and Collector

    Do infra red rays spread out or do they work the same as lasers and fire in a single ray? Example if I have the emittor at different distances from the object it is scanning (e.g a ground surface say 10mm and 30mm distances) do the rays spread and further to cover a wider range, or do they...
  9. S

    What happens when a co2 molecule absorbs an infra red photon?

    Its common knowledge that infra red radiation heats up an absorbing solid surface. That is,the em radiation energy is converted into translational KE of the particles of the solid. What happens in the case of an isolated CO2 molecules absorption? Can the EM energy be converted into increased...
  10. D

    Emission of infra red from hot bodies

    I've seen much mention in websites of matt black surfaces being better emitters of infra red than shiny silver ones so if a matt black and shiny silver surface are heated to about 100 deg C the black one will cool down more quickly as a result of this! Doesn't Wien's law state that the amount of...
  11. M

    Infra Red Light: How Electron Movement Creates NIR

    So, I always thought that NIR was created by the motion of atom at they're everyday temperature, but light is an electrons which goes from one energy state to an other, so how does just "shaking" electrons make light?
  12. M

    How to measure the intensity of Infra red

    Hi, Im investigating how infra red is affected in different areas e.g at home, out side, in the dark or in light. To do this i have made a circuit with a photodiode from the company rapid. The problem is that the photodiode is operating as just a switch, saying if the infrared is on or off so i...
  13. M

    Infra red port for board camera

    Does anyone know how to make an infrared port for a board camera to transfer video to a pocket pc, the camera is analog with RCA output.
  14. B

    Question about Herschel experiment which discover Infra red light

    Hi there, I have a question about his experiment. Herschel discovered IR by placing the blacken thermometer next to the red light (out from the prism), since he noticed the TREND OF INCREASING TEMPERATURE proceeded from BLUE (lowest temperature) TO RED (highest temperature). So he wanted to...