what are the infrared and ultrviolet rays.?

Answer 1

Each are types of electromagnetic radiation. Infrared radiation has a wavelength longer than that of visible light. Ultraviolet radation has a wavelength shorter than that of visible light.

Answer 2

both infrared and ultraviolet rays are electromagnetic waves infrared wavelength - above 700nm freq - in THz range (10^12)
ultraviolet wavelength - above 400nm freq-in PHz range(10^15)
thus it is seen that both act as borders to visible light whose wavelength range is 400-700nm ie. VIBGYOR note: violet-400nm and red-700nm. both infrared and uv rays are invisible because they are beyond the visible spectrum. the infrared rays are produced by the molecules of and hot body.
uv rays are produced by atoms and molecules in electrical discharge. sun is a very powerful source of uv rays. uv can also interact with the atoms in the upper atmosphere producing a large number of ions and hence the atmosphere at a height of 90 km is highly ionised. it is for this reason, the region is called 'ionosphere'

Answer 3

If you heard the term spectrum, the two end lights or rays are infrared and ultraviolet,
these both rays are invisble too the eyes and need speciall equipment too see, infrared is of red color, and is usually used in remotes, a high qulity of infrared is used in laser beams .

ultra volet is violet (purple shade) and is used in medical trement or in eraseing cmos (ic or chips) in electronics.

Answer 4

They are two wavelength of rays emitted by sun Infra red is visible to eyes and felt as heat, whereas Ultra Voilet rays are invisible.

These rays are responsible for Global Warming, while Infra red rays increase the heat over earth, Ultra voilet rays are blocked by Ozone in our atmosphere.

Answer 5

infrared - rays having wavelight greater than red light of the visible light
ultraviolet- rays having wavelight less than voilet light of the visible light

Answer 6

Infrared is light at wavelengths a bit longer than
visible light.
Ultraviolet is at wavelengths a bit shorter.

Answer 7

well,infra red rays r those rays whose frequency is less than the frequency of red light
ultraviolet rays r those whose frequency is more than the frequency of violet
both these rays r not visibile 2 us

Answer 8

Just different "colors" of light that are just outside the range we can see.

Answer 9

They must be different from satyajit ray.

Answer 10

INFRARED RAYS

These rays were discovered in 1800 by William Herschel, a British musician and astronomer, when he observed that a thermometer placed just outside the visible spectrum of sunlight shows a greater increase in temperature than one placed in the red region.
The Infrared region of the spectrum lies beyond the red end of the visible range, with wavelengths between 0.01 to 7.5x10-5 cm.
Instruments for detecting infrared radiation include heat-sensitive devices such as thermocouple detectors, bolometers, photovoltaic cells, and photoconductors.Infrared radiation is absorbed and emitted by the movement (rotations and vibrations) of chemically bonded atoms or groups of atoms of many materials. Some of the materials that absorb infrared radiation are window glass, water and also our atmosphere. Although invisible to the eye, longer infrared radiation can be detected as warmth by the skin. It forms nearly 50% of the Sun's radiant energy, with major portion of the rest being in the visible region.One of the major uses of infrared rays is Infrared photography. Infrared rays are also reflected off objects, just as visible light. Special films or sensors which have the property to 'see in the dark' are used to observe these rays, which enhance different areas according to their heat emission. For e.g., in an infrared photograph, blue sky and water appear nearly black, whereas unexposed skin shows up brightly.Infrared photography is used to detect pathological tissue growths (thermography) and defects in electronic systems and circuits (due to their increased emission of heat). They can also be used to detect heat leaks in houses and forest fires. Shorter infrared rays are used in remote controls.Physiotherapists use infrared radiation to warm damaged muscles and so speed up healing. Infrared light can also be sent down optical fibres for cable television and phone links.Atmospheric haze and certain pollutants that scatter visible light are nearly transparent to parts of the infrared spectrum (scattering efficiency increases with the fourth power of the frequency). Infrared photography of distant objects from the air takes advantage of this phenomenon, to observe cosmic objects through large clouds of interstellar dust. However, since water vapour, O3 and CO2 in the atmosphere absorb large parts of the infrared spectrum, most infrared astronomical observations are carried out at high altitudes, with the help of balloons, rockets and space-crafts.The infrared absorption and emission characteristics of materials yield important information about the size, shape, and chemical bonding of molecules, atoms and ions present in them. Infrared spectroscopy is a powerful tool for determining the internal structure of molecules and for identifying the amounts of known species in a given sample. Infrared rays emitted by a given substance indicate the difference of some of the internal energy states, which depend on atomic weight and other atomic properties.Hence, besides for identification, infrared rays can also be used to determine the amount of a known material in a given substance. Infrared spectroscopy is also used to examine archaeological specimens and for detecting forgeries of art and other objects, which, under visible light, resemble the original.Infrared radiation plays an important role in heat transfer and is integral to the greenhouse effect.Powerful infrared radiations can be artificially prepared, by using gases like Carbon dioxide and Carbon mono-oxide, and can be used in light radar systems and to modify chemical reactions.
Virtually every object at the Earth's surface emits electromagnetic radiation primarily in the infrared region of the spectrum. Man-made sources of infrared radiation include, besides hot objects, infrared light-emitting diodes (LEDs) and lasers, which are used in some fibre-optic communication systems and light radar systems respectively.Other applications of infrared light include its use in remote controls, automatic self-focusing cameras, security alarm systems, and night-vision optical instruments.

ULTRAVIOLET RAYS

The German physicist Johann Wilhelm Ritter, in 1801, found that there exist invisible rays beyond the violet end of the visible spectrum of the Sun that darken silver chloride even more efficiently than visible light. This spectral region between visible light and X-rays was found to be more chemically active than visible light, and named as the ultraviolet region.Ultra-violet rays can have wavelengths as short as 10-9m. They have high frequencies, though not as much a penetrating power to sufficiently penetrate the skin. They are invisible to human eyes, but can be seen by many insects.Ultra-violet radiation of very short wavelengths can be very harmful to the skin, and are responsible for causing our sunburns. Tanning and natural body pigments prevent the destruction of skin cells by ultraviolet light to a certain extent. But prolonged exposure can cause skin cancer, cataract and damage to the human immune system.However, we are protected from the large amounts that the Sun releases by the layer of Ozone gas in the atmosphere, which absorbs a major part of the small-wavelength rays. A small dose of UV rays is though beneficial to the human body, and can be used to treat some skin deseases as they can kill some harmful bacteria. Scientists today, have developed a UV index to help people protect themselves from these harmful ultraviolet waves.Sources of UV rays include our Sun, synchrotron radiation sources, mercury or xenon arc lamps, and gaseous discharge tubes filled with gas atoms like mercury, deytrerium and hydrogen, whose internal electron energy levels correspond to the photons of ultraviolet light.
When ultraviolet light strikes certain materials, it causes them to fluoresce - emit electromagnetic radiation of lower energy. The spectrum of this fluorescent light reflects the material's composition and thus can be used for screening minerals, detecting bacteria in spoiled food, identifying pigments, detecting forgeries of artworks and other objects. For e.g. the fluorescence emitted by the surface of ancient marble is yellow-green, whereas a freshly cut marble surface emits bright violet fluorescence.
The high energy of ultraviolet light gives rise to certain photochemical reactions. This characteristic is exploited to produce impressions on fabrics and for blueprinting design drawings, and also for photolithography and the processing of the microelectronic circuits. Ionized atomic O2, N2 and NO2 are produced in the upper atmosphere by absorption of solar UV radiation. This ionized region is the Ionosphere. UV wavelenghts are also used in astronomical observations.Optical instruments for UV rays are made of special materials like quartz, certain silicates, and metal fluorides, which are transparent in the near ultraviolet. Far ultraviolet radiation is absorbed by nearly all gases and materials. and hence requires reflection optics in vacuum chambers.Ultraviolet radiation is detected by photographic plates and by photoelectric effect in photomultiplier tubes. It can also be converted to visible light by fluorescence before detection.The layer of ozone (O3) that protects us from the ultra-violet radiation emitted by the Sun, by absorbing the short wavelength ultraviolet rays (between 2000 and 2900 Å), and attenuates those with higher wavelengths, is produced about 10 to 50 kilometres above the Earth's surface by reaction between upward-diffusing molecular oxygen (O2) and downward-diffusing ionized atomic oxygen (O+).Many scientists today believe that this life-protecting stratospheric ozone layer is being reduced by the chlorofluorocarbon gases released into the atmosphere by different sources on the earth. Many envieonment groups are vehemently protesting against the use of these gases, and their use in many places in the world has been banned. Pollution on the earth has already caused a hole in the ozone layer above the Antarctic.