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.The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation.^ This frequency means the radiation is in the microwave region of the electromagnetic spectrum.

 ^ The EM spectrum is the range of all possible EM radiation.
  • Spectrum - SourceWatch 19 January 2010 18:018 UTC www.sourcewatch.org [Source type: FILTERED WITH BAYES]

 ^ Invisible, electromagnetic radiation beyond red light on the spectrum, with wavelengths greater than 0.7 microns.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 [1] .The "electromagnetic spectrum" of an object is the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object.^ Several types of spectra can be distinguished depending upon the nature of the radiation coming from an object: If the spectrum is composed primarily of thermal radiation emitted by the object itself, an emission spectrum occurs.

 ^ At tE, matter and radiation would have decoupled, leaving behind a characteristic "black body" spectrum.
  • Council for Christian Colleges & Universities - Integrative Topics in Modern Physics 19 January 2010 18:018 UTC www.cccu.org [Source type: FILTERED WITH BAYES]

 ^ The different types of electromagnetic radiation will serve as the "defendants" who are accused of properties which may or may not be true for that particular wavelength.
.The electromagnetic spectrum extends from below frequencies used for modern radio to gamma radiation at the short-wavelength end, covering wavelengths from thousands of kilometers down to a fraction of the size of an atom.^ Thus, electromagnetic radiation is then grouped into categories based on its wavelength or frequency into the electromagnetic spectrum.
  • Electromagnetic Radiation - ChemWiki 19 January 2010 18:018 UTC chemwiki.ucdavis.edu [Source type: FILTERED WITH BAYES]

 ^ At the furthest known reaches of the electromagnetic spectrum are gamma rays, ultra high-frequency, high-energy, and short-wavelength forms of radiation.

 ^ This frequency means the radiation is in the microwave region of the electromagnetic spectrum.

 .The long wavelength limit is the size of the universe itself, while it is thought that the short wavelength limit is in the vicinity of the Planck length, although in principle the spectrum is infinite and continuous.^ For parts of the electromagnetic spectrum with a low frequency and long wavelength, photon energy is relatively low; but for parts with a high frequency and shortwave length, the value of photon energy is very high.

 ^ At the furthest known reaches of the electromagnetic spectrum are gamma rays, ultra high-frequency, high-energy, and short-wavelength forms of radiation.

 ^ The invisible rays of the spectrum that are outside of the visible spectrum at its short-wavelength violet end.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]
Although some radiations are marked as N for no in the diagram, some waves do in fact penetrate the atmosphere, although extremely minimally compared to the other radiations
Legend[2][3][4]
γ= Gamma rays MIR= Mid infrared HF= High freq.
HX= Hard X-Rays FIR= Far infrared MF= Medium freq.
SX= Soft X-Rays Radio waves LF= Low freq.
EUV= Extreme ultraviolet EHF= Extremely high freq. VLF= Very low freq.
NUV= Near ultraviolet SHF= Super high freq. VF/ULF= Voice freq.
Visible light UHF= Ultra high freq. SLF= Super low freq.
NIR= Near Infrared VHF= Very high freq. ELF= Extremely low freq.
Freq=Frequency

Contents

Range of the spectrum

.EM waves are typically described by any of the following three physical properties: the frequency f, wavelength λ, or photon energy E.^ As a wave, it is represented by velocity, wavelength, and frequency.
  • Electromagnetic Radiation - ChemWiki 19 January 2010 18:018 UTC chemwiki.ucdavis.edu [Source type: FILTERED WITH BAYES]

 ^ What is the frequency of a wave with a wavelength of 500 pm?
  • Electromagnetic Radiation - ChemWiki 19 January 2010 18:018 UTC chemwiki.ucdavis.edu [Source type: FILTERED WITH BAYES]

 ^ What is the wavelength of a wave with a frequency of 4.28 Hz?
  • Electromagnetic Radiation - ChemWiki 19 January 2010 18:018 UTC chemwiki.ucdavis.edu [Source type: FILTERED WITH BAYES]

 .Frequencies range from 2.4x1023 Hz (1 GeV gamma rays) down to the local plasma frequency of the ionized interstellar medium (~1 kHz).^ In the electromagnetic spectrum, long wavelengths correspond to the radio frequency spectrum, intermediate wavelengths to millimeter and infrared radiation, short wavelengths to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ At the furthest known reaches of the electromagnetic spectrum are gamma rays, ultra high-frequency, high-energy, and short-wavelength forms of radiation.

 ^ Between about 10 13 and 10 17 Hz on the electromagnetic spectrum is the range of light: infrared, visible, and ultraviolet.

 .Wavelength is inversely proportional to the wave frequency, so gamma rays have very short wavelengths that are fractions of the size of atoms, whereas wavelengths can be as long as the universe.^ Complete range of electromagnetic radiation, from very short-wavelength (high-frequency) gamma-rays, through X-rays and ultraviolet light to the small range of visible light, and further to infrared radiation, microwave, and the comparatively long-wavelength low-frequency radio waves.

 ^ For parts of the electromagnetic spectrum with a low frequency and long wavelength, photon energy is relatively low; but for parts with a high frequency and shortwave length, the value of photon energy is very high.

 ^ Wavelength, symbolized λ (the Greek letter lambda) is mathematically related to wave speed, period, and frequency.

 .Photon energy is directly proportional to the wave frequency, so gamma rays have the highest energy (around a billion electron volts) and radio waves have very low energy (around femto electron volts).^ Frequency is directly proportional to energy and can be express as: .
  • Electromagnetic Radiation - ChemWiki 19 January 2010 18:018 UTC chemwiki.ucdavis.edu [Source type: FILTERED WITH BAYES]

 ^ Radio waves have the lowest energy levels.
  • Electromagnetic Radiation - ChemWiki 19 January 2010 18:018 UTC chemwiki.ucdavis.edu [Source type: FILTERED WITH BAYES]

 ^ For parts of the electromagnetic spectrum with a low frequency and long wavelength, photon energy is relatively low; but for parts with a high frequency and shortwave length, the value of photon energy is very high.

 These relations are illustrated by the following equations:
f = \frac{c}{\lambda}     or     f = \frac{E}{h}     or     E=\frac{hc}{\lambda}
Where:
c = 299,792,458 m/s (speed of light in vacuum) and
h = 6.626\ 068\ 96(33) imes 10^{-34}\ \mbox{J s} = 4.135\ 667\ 33(10) imes 10^{-15}\ \mbox{eV s} (Planck's constant).
.Whenever electromagnetic waves exist in a medium with matter, their wavelength is decreased.^ The transfer of energy by means of electromagnetic waves, which require no physical medium (for example, water or air) for the transfer.

 ^ The electromagnetic spectrum is the complete range of electromagnetic waves on a continuous distribution from a very low range of frequencies and energy levels, with a correspondingly long wavelength, to a very high range of frequencies and energy levels, with a correspondingly short wavelength.

 ^ The complete range of electromagnetic waves on a continuous distribution from a very low range of frequencies and energylevels, with a correspondingly long wavelength, to a very high range of frequencies and energy levels, with a correspondingly short wavelength.

 .Wavelengths of electromagnetic radiation, no matter what medium they are traveling through, are usually quoted in terms of the vacuum wavelength, although this is not always explicitly stated.^ In a vacuum, all electromagnetic radiation travels at the speed of light.

 ^ Contributors Electromagnetic radiation (EMR) is a form of energy that is produced by oscillating electric and magnetic disturbance, or by the movement of electrically charged particles traveling through a vacuum or matter.
  • Electromagnetic Radiation - ChemWiki 19 January 2010 18:018 UTC chemwiki.ucdavis.edu [Source type: FILTERED WITH BAYES]

 ^ Invisible, electromagnetic radiation beyond red light on the spectrum, with wavelengths greater than 0.7 microns.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]
.Generally, EM radiation is classified by wavelength into radio wave, microwave, infrared, the visible region we perceive as light, ultraviolet, X-rays and gamma rays.^ In the electromagnetic spectrum, long wavelengths correspond to the radio frequency spectrum, intermediate wavelengths to millimeter and infrared radiation, short wavelengths to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ FYI, Infrared and Ultraviolet are not classified as light on the electromagnetic spectrum.
  • Light Spectrum and Color Temperature 15 September 2009 8:31 UTC www.thekrib.com [Source type: FILTERED WITH BAYES]

 ^ Included on the electromagnetic spectrum are radio waves and microwaves; infrared, visible, and ultraviolet light; x rays, and gamma rays.

 The behavior of EM radiation depends on its wavelength. .When EM radiation interacts with single atoms and molecules, its behavior also depends on the amount of energy per quantum (photon) it carries.^ The amount of energy radiated at each range of wavelengths.

 ^ Typically 1-10 eV is the amount of energy per atom involved in chemical reactions.

 ^ Electrons are found in shells surrounding the nuclei of atoms; their interactions with the electrons of neighboring atoms create the chemical bonds that link atoms together as molecules.
.Spectroscopy can detect a much wider region of the EM spectrum than the visible range of 400 nm to 700 nm.^ But if it's harvesting a much wider spectrum?
  • OhGizmo! » Archive » [CES 2010] RCA Airnergy Charger Harvests Electricity From WiFi Signals 19 January 2010 18:018 UTC www.ohgizmo.com [Source type: Original source]

 ^ The color regions of the Visible Spectrum .
  • Electromagnetic Radiation - ChemWiki 19 January 2010 18:018 UTC chemwiki.ucdavis.edu [Source type: FILTERED WITH BAYES]

 ^ Between about 10 13 and 10 17 Hz on the electromagnetic spectrum is the range of light: infrared, visible, and ultraviolet.

 .A common laboratory spectroscope can detect wavelengths from 2 nm to 2500 nm.^ Chlorophyll , the green pigment common to all photosynthetic cells, absorbs all wavelengths of visible light except green, which it reflects to be detected by our eyes.

 .Detailed information about the physical properties of objects, gases, or even stars can be obtained from this type of device.^ If a little bit of the voice information is garbled or lost in a transfer between locations, or if interference from other devices somehow affects the transmission, there is nothing that can be done about it.
  • 4 G Wireless Systems 19 January 2010 18:018 UTC www.myplick.com [Source type: FILTERED WITH BAYES]

 Spectroscopes are widely used in astrophysics. .For example, many hydrogen atoms emit a radio wave photon which has a wavelength of 21.12 cm.^ Unlike many other radio services with which it shares the radio frequency spectrum, radio astronomy is a passive service and deals only with the reception of radio waves—cosmic radio waves.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ For example, an orbital electron can exist only in those energy levels that correspond to an integral number of deBroglie wavelengths in a Bohr atom.

 ^ Whereas AM is an example of a long-wave radio transmission, FM is on the microwave sector of the electromagnetic spectrum, along with television and radar.

 .Also, frequencies of 30 Hz and below can be produced by and are important in the study of certain stellar nebulae[6] and frequencies as high as 2.9×1027 Hz have been detected from astrophysical sources.^ High frequencies are expressed in terms of kilohertz (kHz; 10 3 or1,000 cycles per second); megahertz (MHz;10 6 or 1 million cycles per second); and gigahertz (GHz; 10 9 or 1 billion cycles per second.

 ^ Typically, signals from spacecraft are sent in a range above 10 10 Hz, far above the frequencies of most microwave transmissions for commercial purposes.

 ^ The range of frequencies for waves in the electromagnetic spectrum is from approximately 10 2 Hz to more than 10 25 Hz.

 [7]

Rationale

.Electromagnetic radiation interacts with matter in different ways in different parts of the spectrum.^ Invisible, electromagnetic radiation beyond red light on the spectrum, with wavelengths greater than 0.7 microns.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 ^ For parts of the electromagnetic spectrum with a low frequency and long wavelength, photon energy is relatively low; but for parts with a high frequency and shortwave length, the value of photon energy is very high.

 ^ But our concern in the present context is with electromagnetic radiation, of which the waves on the electromagnetic spectrum are a particularly significant example.

 The types of interaction can be so different that it seems to be justified to refer to different types of radiation. .At the same time, there is a continuum containing all these "different kinds" of electromagnetic radiation.^ However, all these astronomical observations were in the visible portion of the electromagnetic spectrum.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ Packets can also travel across the network right after each other or separated by packets from other devices; they can all take the same route over networks or each take a different route.
  • 4 G Wireless Systems 19 January 2010 18:018 UTC www.myplick.com [Source type: FILTERED WITH BAYES]

 ^ I guess they use this principle to control the growth and flowering of various flowering plants offered commercially so they all come into bloom at the same (chosen) time.
  • Light Spectrum and Color Temperature 15 September 2009 8:31 UTC www.thekrib.com [Source type: FILTERED WITH BAYES]

 Thus we refer to a spectrum, but divide it up based on the different interactions with matter.
Region of the spectrum Main interactions with matter
Radio Collective oscillation of charge carriers in bulk material (plasma oscillation). An example would be the oscillation of the electrons in an antenna.
Microwave through far infrared Plasma oscillation, molecular rotation
Near infrared Molecular vibration, plasma oscillation (in metals only)
Visible Molecular electron excitation (including pigment molecules found in the human retina), plasma oscillations (in metals only)
Ultraviolet Excitation of molecular and atomic valence electrons, including ejection of the electrons (photoelectric effect)
X-rays Excitation and ejection of core atomic electrons, Compton scattering (for low atomic numbers)
Gamma rays Energetic ejection of core electrons in heavy elements, Compton scattering (for all atomic numbers), excitation of atomic nuclei, including dissociation of nuclei
High energy gamma rays Creation of particle-antiparticle pairs. At very high energies a single photon can create a shower of high energy particles and antiparticles upon interaction with matter.

Types of radiation

The electromagnetic spectrum
.While the classification scheme is generally accurate, in reality there is often some overlap between neighboring types of electromagnetic energy.^ Do some of the wave type classifications overlap somewhat?
  • Light and the Electromagnetic Spectrum 19 January 2010 18:018 UTC www.cdli.ca [Source type: FILTERED WITH BAYES]

 ^ While the classification scheme is generally accurate, in reality there is often some overlap between neighboring types of electromagnetic energy.
  • Electromagnetic spectrum 19 January 2010 18:018 UTC articles.gourt.com [Source type: FILTERED WITH BAYES]
  • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

 ^ A. There are no sharp distinctions between regions, many regions overlap.
  • electromagneticspectrum (carusomb) 19 January 2010 18:018 UTC sites.google.com [Source type: FILTERED WITH BAYES]

 .For example, SLF radio waves at 60 Hz may be received and studied by astronomers, or may be ducted along wires as electric power, although the latter is, strictly speaking, not electromagnetic radiation at all (see Near and far field) The distinction between X and gamma rays is based on sources: gamma rays are the photons generated from nuclear decay or other nuclear and subnuclear/particle process, whereas X-rays are generated by electronic transitions involving highly energetic inner atomic electrons.^ The connection between electromagnetic radiation and electromagnetic force is far from obvious.

 ^ Electromagnetic waves are an example of electromagnetism.

 ^ "Waves" of electrical and magnetic "disturbance", radiated as visible light, radio waves, or any other manifestation of the electromagnetic spectrum.

 .Generally, nuclear transitions are much more energetic than electronic transitions, so usually, gamma-rays are more energetic than X-rays, but exceptions exist.^ In the standard model there are two families of particles (quarks and leptons) that are comprised of three "generations" of particles, where each generation is more massive than the previous generation.
  • Council for Christian Colleges & Universities - Integrative Topics in Modern Physics 19 January 2010 18:018 UTC www.cccu.org [Source type: FILTERED WITH BAYES]

 ^ A Xennon arc (electronic flash tube) is full spectrum but emits more light in the blue and green than the red, and usually has a high Kelvin rating, 9,000 -10,000 Kelvin if they are not filtered.
  • Light Spectrum and Color Temperature 15 September 2009 8:31 UTC www.thekrib.com [Source type: FILTERED WITH BAYES]

 ^ The range of photon energy in the electromagnetic spectrum is from about 10 −13 to more than 10 10 electron volts.

 .By analogy to electronic transitions, muonic atom transitions are also said to produce X-rays, even though their energy may exceed 6 megaelectronvolts (0.96 pJ),[8] whereas there are many (77 Known to be less than 10 keV (1.6 fJ)) low-energy nuclear transitions (e.g.^ Whereas conduction of convection can only take place where there is matter, which provides a medium for the energy transfer, radiation requires no medium.

 ^ [H76] (b) The allowed energy states for electrons orbiting the nucleus of an atom.

 ^ The range of photon energy in the electromagnetic spectrum is from about 10 −13 to more than 10 10 electron volts.

 the .7.6 eV (1.22 aJ) nuclear transition of Th-229), and despite being one million-fold less energetic than some muonic X-rays, the emitted photons are still called gamma rays due to their nuclear origin.^ The ultra-short wavelengths of gamma rays, after all, are equal to one-trillionth of a centimeter.

 ^ Sorry, but your theory makes less sense than the original.
  • OhGizmo! » Archive » [CES 2010] RCA Airnergy Charger Harvests Electricity From WiFi Signals 19 January 2010 18:018 UTC www.ohgizmo.com [Source type: Original source]

 ^ The energy of is inversely porportional to the wavelength: longer wavelengths have less energy than do shorter ones.

 [9]
.Also, the region of the spectrum of the particular electromagnetic radiation is reference-frame dependent (on account of the Doppler shift for light) so EM radiation which one observer would say is in one region of the spectrum could appear to an observer moving at a substantial fraction of the speed of light with respect to the first to be in another part of the spectrum.^ In a vacuum, all electromagnetic radiation travels at the speed of light.

 ^ Visible light is one small part of the electromagnetic spectrum.

 ^ An interesting point but one wonders whether our "illusion" of the universe would hold up across the entire electromagnetic spectrum from the atomic to the micro to the macro and continue to bemuse us even in all our multidisciplinary imagery?
  • The Infinite Universe (kst) - sci.astro.amateur | Google Groups 19 January 2010 18:018 UTC groups.google.com.au [Source type: FILTERED WITH BAYES]

 For example, consider the cosmic microwave background. .It was produced, when matter and radiation decoupled, by the de-excitation of hydrogen atoms to the ground state.^ At tE, matter and radiation would have decoupled, leaving behind a characteristic "black body" spectrum.
  • Council for Christian Colleges & Universities - Integrative Topics in Modern Physics 19 January 2010 18:018 UTC www.cccu.org [Source type: FILTERED WITH BAYES]

 .These photons were from Lyman series transitions, putting them in the ultraviolet (UV) part of the electromagnetic spectrum.^ For parts of the electromagnetic spectrum with a low frequency and long wavelength, photon energy is relatively low; but for parts with a high frequency and shortwave length, the value of photon energy is very high.

 ^ In the electromagnetic spectrum, long wavelengths correspond to the radio frequency spectrum, intermediate wavelengths to millimeter and infrared radiation, short wavelengths to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ Between about 10 13 and 10 17 Hz on the electromagnetic spectrum is the range of light: infrared, visible, and ultraviolet.

 .Now this radiation has undergone enough cosmological red shift to put it into the microwave region of the spectrum for observers moving slowly (compared to the speed of light) with respect to the cosmos.^ The velocity of such radiation in a vacuum is the speed of light.

 ^ The role of the light cone in dividing spacetime into regions called the absolute past, absolute future and absolute elsewhere was discussed.
  • Council for Christian Colleges & Universities - Integrative Topics in Modern Physics 19 January 2010 18:018 UTC www.cccu.org [Source type: FILTERED WITH BAYES]

 ^ If you were to look at a graph of the visible light spectrum the cool white bulbs have a large spike in the green region and some smaller spikes in the blue and only negligible stuff in the red.
  • Light Spectrum and Color Temperature 15 September 2009 8:31 UTC www.thekrib.com [Source type: FILTERED WITH BAYES]

 .However, for particles moving near the speed of light, this radiation will be blue-shifted in their rest frame.^ Remember, however, that the energy level identified is for a photon—a light particle.

 ^ The velocity of such radiation in a vacuum is the speed of light.

 ^ In a vacuum, all electromagnetic radiation travels at the speed of light.

 .The highest energy cosmic ray protons are moving such that, in their rest frame, this radiation is blueshifted to high energy gamma rays which interact with the proton to produce bound quark-antiquark pairs (pions).^ In the electromagnetic spectrum, long wavelengths correspond to the radio frequency spectrum, intermediate wavelengths to millimeter and infrared radiation, short wavelengths to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ At the furthest known reaches of the electromagnetic spectrum are gamma rays, ultra high-frequency, high-energy, and short-wavelength forms of radiation.

 ^ (In cosmic-ray studies, a plot of number of particles versus energy.

 This is the source of the GZK limit.

Radio frequency

Main articles: Radio frequency, Radio spectrum, and Radio waves
.Radio waves generally are utilized by antennas of appropriate size (according to the principle of resonance), with wavelengths ranging from hundreds of meters to about one millimeter.^ Depending on the wavelength, an electromagnetic wave can be a radio wave, a microwave, an infrared wave, a wave of visible light, an ultraviolet wave, a beam of X rays, or a beam of gamma rays.

 ^ According > to the "pure H2O" curve, which is the one relevant for this purpose, a > 16" layer of pure water should absob 15-20 % of the ligth at the 600-700 > nm band, about 5% at the visible range and nothing at the blue.
  • Light Spectrum and Color Temperature 15 September 2009 8:31 UTC www.thekrib.com [Source type: FILTERED WITH BAYES]

 ^ You can direct the output from hundreds of WiFi signals to the antenna in the device but the bottlneck is still the efficiency and size of the antenna.
  • OhGizmo! » Archive » [CES 2010] RCA Airnergy Charger Harvests Electricity From WiFi Signals 19 January 2010 18:018 UTC www.ohgizmo.com [Source type: Original source]

 .They are used for transmission of data, via modulation.^ Once encoded, the data is modulated for transmission over the bandwidth allocated for that transmission.
  • 4 G Wireless Systems 19 January 2010 18:018 UTC www.myplick.com [Source type: FILTERED WITH BAYES]

 ^ Since the beginning of the Internet over 30 years ago, packets have been used for all data transmission.
  • 4 G Wireless Systems 19 January 2010 18:018 UTC www.myplick.com [Source type: FILTERED WITH BAYES]

 .Television, mobile phones, wireless networking and amateur radio all use radio waves.^ The radio waves travel twice as far as higher frequencies, which makes 700 MHz particularly suitable for wireless service and significantly reduces the capital cost of building out a network.
  • Spectrum - SourceWatch 19 January 2010 18:018 UTC www.sourcewatch.org [Source type: FILTERED WITH BAYES]

 ^ WHO Director General on children & mobile phone use: .
  • Electromagnetic Radiation - Free Article 19 January 2010 18:018 UTC www.latitudes.org [Source type: FILTERED WITH BAYES]

 ^ Maisch D. "Mobile Phone Use: its time to take precautions" ACNEM .
  • Electromagnetic Radiation - Free Article 19 January 2010 18:018 UTC www.latitudes.org [Source type: FILTERED WITH BAYES]

 .The use of the radio spectrum is regulated by many governments through frequency allocation.^ UWB uses all frequencies from high to low, thereby passing through objects like the sea or layers of rock.
  • 4 G Wireless Systems 19 January 2010 18:018 UTC www.myplick.com [Source type: FILTERED WITH BAYES]

 ^ Software Defined Radio A software defined radio is one that can be configured to any radio or frequency standard through the use of software.
  • 4 G Wireless Systems 19 January 2010 18:018 UTC www.myplick.com [Source type: FILTERED WITH BAYES]

 ^ The entire range of the electromagnetic spectrum used for radio, television, cellular and wireless communications runs from 3 kilohertz (khz) to 300 Gigahertz (GHz).
  • Spectrum - SourceWatch 19 January 2010 18:018 UTC www.sourcewatch.org [Source type: FILTERED WITH BAYES]
.Radio waves can be made to carry information by varying a combination of the amplitude, frequency and phase of the wave within a frequency band.^ It has provided information on the atmospheric absorption of radio waves, important in the area of telecommunications and communications technology.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ Unlike many other radio services with which it shares the radio frequency spectrum, radio astronomy is a passive service and deals only with the reception of radio waves—cosmic radio waves.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ The 4g wireless uses Orthogonal Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band (UWB), and Millimeter wireless.
  • 4 G Wireless Systems 19 January 2010 18:018 UTC www.myplick.com [Source type: FILTERED WITH BAYES]

 .When EM radiation impinges upon a conductor, it couples to the conductor, travels along it, and induces an electric current on the surface of that conductor by exciting the electrons of the conducting material.^ These electrons can create an electrical current.

 ^ In degenerate matter electron conduction, not radiation, is the main mechanism of energy transport.

 This effect (the skin effect) is used in antennas. .EM radiation may also cause certain molecules to absorb energy and thus to heat up, causing thermal effects and sometimes burns.^ The telecom industry, and the FCC's safe exposure guidelines, recognize only thermal (heating) effects.
  • Electromagnetic Radiation - Free Article 19 January 2010 18:018 UTC www.latitudes.org [Source type: FILTERED WITH BAYES]

 ^ These are called "nonthermal effects" because they occur at levels too low to cause tissue heating.
  • Electromagnetic Radiation - Free Article 19 January 2010 18:018 UTC www.latitudes.org [Source type: FILTERED WITH BAYES]

 ^ Energy from the sun reaches the earth by radiation, and a person's body can lose heat to a cold window or skylight surface in a similar way.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 This is exploited in microwave ovens.

Microwaves

Main article: Microwaves
Plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation.
.The super high frequency (SHF) and extremely high frequency (EHF) of microwaves come next up the frequency scale.^ Included in this broad sub-spectrum, with frequencies up to about 10 7 Hertz, are long-wave radio, short-wave radio, and microwaves.

 ^ As noted earlier, gigahertz, or units of 1 billion Hertz, are often used in describing extremely high frequencies, in which case the number is written as 10 16 GHz.

 .Microwaves are waves which are typically short enough to employ tubular metal waveguides of reasonable diameter.^ Though microwaves are treated separately from radio waves, in fact, they are just radio signals of a very short wavelength.

 ^ Typical spectrally selective coatings are transparent to visible light and reflect short-wave and long-wave infrared radiation.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 ^ A typical type of low-E coating is transparent to the solar spectrum (visible light and short-wave infrared radiation) and reflective of long-wave infrared radiation.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 .Microwave energy is produced with klystron and magnetron tubes, and with solid state diodes such as Gunn and IMPATT devices.^ In quantum mechanics, the matrix M will correspond to a particular dynamical variable (such as position, energy or momentum) and will correspond to the value obtained by measuring that dynamical variable if the system is in the state described by .

 ^ A range of energies in a solid for which there are no quantum states of the electrons.

 ^ In the first microwaves, the only settings were "on" and "off," because there were only two possible adjustments: either the magnetron would produce, or not produce, microwaves.

 Microwaves are absorbed by molecules that have a dipole moment in liquids. .In a microwave oven, this effect is used to heat food.^ The currents produce a heating effect corresponding to a loss of useful energy ( eddy-current loss ).

 ^ Well, the microwaves in a microwave oven are at the natural frequency of water molecules, so that they collide with other molecules and heat the food.
  • xkcd • View topic - "Electromagnetic Spectrum" Discussion 19 January 2010 18:018 UTC forums.xkcd.com [Source type: FILTERED WITH BAYES]

 .Low-intensity microwave radiation is used in Wi-Fi, although this is at intensity levels unable to cause thermal heating.^ New Mexico man sues neighbor for using wi-fi .
  • Mobile & wireless | ITworld 19 January 2010 18:018 UTC www.itworld.com [Source type: News]

 ^ It most likely has some wi-fi reactive material that vibrates or moves at the 2.4 Ghz (or whatever) signal, which causes physical motion which charges the battery.
  • OhGizmo! » Archive » [CES 2010] RCA Airnergy Charger Harvests Electricity From WiFi Signals 19 January 2010 18:018 UTC www.ohgizmo.com [Source type: Original source]

 ^ Operation of an RF radiation source also exposes others, in the near proximity, to similarly biologically active levels of electromagnetic field intensities 15 .
  • Electromagnetic Radiation - Free Article 19 January 2010 18:018 UTC www.latitudes.org [Source type: FILTERED WITH BAYES]
.Volumetric heating, as used by microwaves, transfer energy through the material electromagnetically, not as a thermal heat flux.^ An inert, nontoxic gas used in insulating windows to reduce heat transfer.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 ^ This is because the microwave frequencies used by these technologies, identical to the frequencies used in a microwave oven, pass through walls and do not respect the boundaries of classrooms.
  • Electromagnetic Radiation - Free Article 19 January 2010 18:018 UTC www.latitudes.org [Source type: FILTERED WITH BAYES]

 ^ The use of low-conductance spacers to reduce heat transfer near the edge of insulated glazing.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 .The benefit of this is a more uniform heating and reduced heating time; microwaves can heat material in less than 1% of the time of conventional heating methods.^ It is 10 times more sensitive to green than to blue or red.
  • Light Spectrum and Color Temperature 15 September 2009 8:31 UTC www.thekrib.com [Source type: FILTERED WITH BAYES]

 ^ More expensive than conventional light bulbs Not as energy efficient as Fluorescent bulbs .
  • Full Spectrum Lighting Ratings, Reviews in Handy Buyers Guide Chart 15 September 2009 8:31 UTC www.allergybuyersclub.com [Source type: General]

 ^ Quote: you'll note that microwaves are less potentially harmful to humans than infrared or visible light I do know that microwaves are non-ionizing radiation.
  • xkcd • View topic - "Electromagnetic Spectrum" Discussion 19 January 2010 18:018 UTC forums.xkcd.com [Source type: FILTERED WITH BAYES]
.When active, the average microwave oven is powerful enough to cause interference at close range with poorly shielded electromagnetic fields such as those found in mobile medical devices and cheap consumer electronics.^ Arthur Firstenberg suffers from electromagnetic sensitivity, which means that cell phones, computers, and wi-fi cause him great pain -- even when those devices reside in the house next door.
  • Mobile & wireless | ITworld 19 January 2010 18:018 UTC www.itworld.com [Source type: News]

 ^ Even if it could work, I do not want such devices to cause an increase of power in WIFI signals emissions everywhere !
  • OhGizmo! » Archive » [CES 2010] RCA Airnergy Charger Harvests Electricity From WiFi Signals 19 January 2010 18:018 UTC www.ohgizmo.com [Source type: Original source]

 ^ The range of photon energy in the electromagnetic spectrum is from about 10 −13 to more than 10 10 electron volts.

Terahertz radiation

Main article: Terahertz radiation
.Terahertz radiation is a region of the spectrum between far infrared and microwaves.^ Terahertz radiation is a region of the spectrum between far infrared and microwaves.
  • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

 ^ This region falls between microwaves (on the long side) and far-infrared (on the short...

 ^ Relatively understudied spectrum of light between far infrared and microwaves.
  • Chemistry - Electromagnetic spectrum 19 January 2010 18:018 UTC www.chemistrydaily.com [Source type: Reference]

 .Until recently, the range was rarely studied and few sources existed for microwave energy at the high end of the band (sub-millimetre waves or so-called terahertz waves), but applications such as imaging and communications are now appearing.^ Using Planck's quantum principles, Einstein, in 1905, showed that light appears in "bundles" of energy, which travel as waves but behave as particles in certain situations.

 ^ The FCC assigned the range of 5.9 to 26.1 MHz to short-wave radio, and later the area of 26.96 to 27.41 MHz to citizens' band (CB) radio.

 ^ When such an effect is observed, a high-resolution MR imaging (or CT) anatomic correlation can be obtained to determine the exact location of the electrode contact responsible for the unexpected effect.
  • Neuroimaging and Deep Brain Stimulation -- Dormont et al. 31 (1): 15 -- American Journal of Neuroradiology 19 January 2010 18:018 UTC www.ajnr.org [Source type: Academic]

 .Scientists are also looking to apply terahertz technology in the armed forces, where high frequency waves might be directed at enemy troops to incapacitate their electronic equipment.^ Higher-frequency waves, all of which can be generally described as light, provide the means for looking deep into the universe—and deep into the human body.

 ^ The electromagnetic spectrum is the complete range of electromagnetic waves on a continuous distribution from a very low range of frequencies and energy levels, with a correspondingly long wavelength, to a very high range of frequencies and energy levels, with a correspondingly short wavelength.

 ^ The complete range of electromagnetic waves on a continuous distribution from a very low range of frequencies and energylevels, with a correspondingly long wavelength, to a very high range of frequencies and energy levels, with a correspondingly short wavelength.

Infrared radiation

Main article: Infrared radiation
.The infrared part of the electromagnetic spectrum covers the range from roughly 300 GHz (1 mm) to 400 THz (750 nm).^ For parts of the electromagnetic spectrum with a low frequency and long wavelength, photon energy is relatively low; but for parts with a high frequency and shortwave length, the value of photon energy is very high.

 ^ Between about 10 13 and 10 17 Hz on the electromagnetic spectrum is the range of light: infrared, visible, and ultraviolet.

 ^ The range of photon energy in the electromagnetic spectrum is from about 10 −13 to more than 10 10 electron volts.

 It can be divided into three parts:
.
  • Far-infrared, from 300 GHz (1 mm) to 30 THz (10 μm).^ The optical spectrum has a frequency range of 300 GHz to 300,000 THz and consists of infrared, visible, and ultraviolet lights.
    • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

     .The lower part of this range may also be called microwaves.^ The lower part of this range may also be called microwaves.
    • Chemistry - Electromagnetic spectrum 19 January 2010 18:018 UTC www.chemistrydaily.com [Source type: Reference]
    • Electromagnetic spectrum 19 January 2010 18:018 UTC articles.gourt.com [Source type: FILTERED WITH BAYES]
    • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

     ^ RF Frequency Converters - (152 companies) RF frequency converters are integrated component assemblies required for converting microwave signals to lower (or intermediate) or higher frequency range for further processing.

     .This radiation is typically absorbed by so-called rotational modes in gas-phase molecules, by molecular motions in liquids, and by phonons in solids.^ Without going into too much detail here, conduction generally involves heat transfer between molecules in a solid; convection takes place in a fluid (a gas such as air or a liquid such as water); and radiation, of course, requires no medium.

     .The water in the Earth's atmosphere absorbs so strongly in this range that it renders the atmosphere effectively opaque.^ Electromagnetic waves in this range are not strongly absorbed by water or the earth.

     ^ The water in the Earth's atmosphere absorbs so strongly in this range that it renders the atmosphere effectively opaque.
    • Chemistry - Electromagnetic spectrum 19 January 2010 18:018 UTC www.chemistrydaily.com [Source type: Reference]
    • Electromagnetic spectrum 19 January 2010 18:018 UTC articles.gourt.com [Source type: FILTERED WITH BAYES]
    • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

     ^ The sun radiates most strongly in this range, and our atmosphere does not absorb it (Los Angeles excepted).

     .However, there are certain wavelength ranges ("windows") within the opaque range which allow partial transmission, and can be used for astronomy.^ However, there are certain wavelength ranges ("windows") within the opaque range which allow partial transmission, and can be used for astronomy.
    • Chemistry - Electromagnetic spectrum 19 January 2010 18:018 UTC www.chemistrydaily.com [Source type: Reference]
    • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

     ^ Common names for the different bands may refer to the wavelength, relative frequency or the type of transmission commonly used.
    • Chemistry - Electromagnetic spectrum 19 January 2010 18:018 UTC www.chemistrydaily.com [Source type: Reference]

     ^ However, most of the energy the sun radiates is in the ultraviolet Ultraviolet radiation is electromagnetic radiation in the wavelength range 13 nm to 380 nm.
    • The Electromagnetic Spectrum 19 January 2010 18:018 UTC www.absorblearning.com [Source type: FILTERED WITH BAYES]

     .The wavelength range from approximately 200 μm up to a few mm is often referred to as "sub-millimetre" in astronomy, reserving far infrared for wavelengths below 200 μm.
  • Mid-infrared, from 30 to 120 THz (10 to 2.5 μm).^ The range of frequencies for waves in the electromagnetic spectrum is from approximately 10 2 Hz to more than 10 25 Hz.

     ^ The water vapor contained in the air is opaque to various wavelengths in the infrared frequency ranges.
    • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

     ^ The optical spectrum has a frequency range of 300 GHz to 300,000 THz and consists of infrared, visible, and ultraviolet lights.
    • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

     .Hot objects (black-body radiators) can radiate strongly in this range.^ At tE, matter and radiation would have decoupled, leaving behind a characteristic "black body" spectrum.
    • Council for Christian Colleges & Universities - Integrative Topics in Modern Physics 19 January 2010 18:018 UTC www.cccu.org [Source type: FILTERED WITH BAYES]

     ^ A measure of the efficiency of a source to radiate like a perfect black body; 0% is perfectly black and 0% is perfectly reflecting.

     It is absorbed by molecular vibrations, where the different atoms in a molecule vibrate around their equilibrium positions. .This range is sometimes called the fingerprint region since the mid-infrared absorption spectrum of a compound is very specific for that compound.
  • Near-infrared, from 120 to 400 THz (2,500 to 750 nm).^ Between about 10 13 and 10 17 Hz on the electromagnetic spectrum is the range of light: infrared, visible, and ultraviolet.

     ^ The range of all electromagnetic waves is called the electromagnetic spectrum.
    • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

     ^ The electromagnetic spectrum is the complete range of electromagnetic waves on a continuous distribution from a very low range of frequencies and energy levels, with a correspondingly long wavelength, to a very high range of frequencies and energy levels, with a correspondingly short wavelength.

     Physical processes that are relevant for this range are similar to those for visible light.

Visible radiation (light)

Main article: Visible spectrum
.Above infrared in frequency comes visible light.^ After infrared comes visible light .
  • Chemistry - Electromagnetic spectrum 19 January 2010 18:018 UTC www.chemistrydaily.com [Source type: Reference]

 ^ Above infrared in frequency comes visible light .
  • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

 ^ In the electromagnetic spectrum, long wavelengths correspond to the radio frequency spectrum, intermediate wavelengths to millimeter and infrared radiation, short wavelengths to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 .This is the range in which the sun and stars similar to it emit most of their radiation.^ This is the range in which the sun and stars similar to it emit most of their radiation.
  • Chemistry - Electromagnetic spectrum 19 January 2010 18:018 UTC www.chemistrydaily.com [Source type: Reference]
  • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

 ^ The Sun emits a large amount of UV radiation, which could quickly turn Earth into a barren desert; however, most of it is absorbed by the atmosphere's ozone layer before reaching the surface.
  • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

 ^ UV radiation is most commonly known because of its severe effects on the skin from the sun, leading to cancer.
  • Electromagnetic Radiation - ChemWiki 19 January 2010 18:018 UTC chemwiki.ucdavis.edu [Source type: FILTERED WITH BAYES]

 .It is probably not a coincidence that the human eye is sensitive to the wavelengths that the sun emits most strongly.^ It is probably not a coincidence that the human eye is sensitive to the wavelengths that the sun emits most strongly.
  • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

 ^ EM radiation with a wavelength between approximately 400 nm and 700 nm is detected by the human eye and perceived as visible light .
  • PowerPedia:Electromagnetic wave - PESWiki 19 January 2010 18:018 UTC peswiki.com [Source type: FILTERED WITH BAYES]

 ^ EM radiation with a wavelength between approximately 400 nm and 700 nm is detected by the human eye and perceived as visible light.
  • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

 .Visible light (and near-infrared light) is typically absorbed and emitted by electrons in molecules and atoms that move from one energy level to another.^ Forest fire in visible light and infrared.
  • The Electromagnetic Spectrum 19 January 2010 18:018 UTC www.absorblearning.com [Source type: FILTERED WITH BAYES]

 ^ Since the energy levels of electrons in atoms are discrete, each element emits and absorbs its own characteristic frequencies.
  • PowerPedia:Electromagnetic wave - PESWiki 19 January 2010 18:018 UTC peswiki.com [Source type: FILTERED WITH BAYES]

 ^ After infrared comes visible light .
  • Chemistry - Electromagnetic spectrum 19 January 2010 18:018 UTC www.chemistrydaily.com [Source type: Reference]

 .The light we see with our eyes is really a very small portion of the electromagnetic spectrum.^ The light we see with our eyes is really a very small portion of the electromagnetic spectrum.
  • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

 ^ The partof the electromagnetic spectrum that we are able to see is the visible light spectrum.
  • Electromagnetic Radiation - ChemWiki 19 January 2010 18:018 UTC chemwiki.ucdavis.edu [Source type: FILTERED WITH BAYES]

 ^ Seeing our World in a Different Light .
  • Browse: Keywords: Electromagnetic spectrum | OER Commons 19 January 2010 18:018 UTC www.oercommons.org [Source type: General]

 .A rainbow shows the optical (visible) part of the electromagnetic spectrum; infrared (if you could see it) would be located just beyond the red side of the rainbow with ultraviolet appearing just beyond the violet end.^ ABout the comic again: It does not show gravity as a part of the electromagnetic spectrum.
  • xkcd • View topic - "Electromagnetic Spectrum" Discussion 19 January 2010 18:018 UTC forums.xkcd.com [Source type: FILTERED WITH BAYES]

 ^ FYI, Infrared and Ultraviolet are not classified as light on the electromagnetic spectrum.
  • Light Spectrum and Color Temperature 15 September 2009 8:31 UTC www.thekrib.com [Source type: FILTERED WITH BAYES]

 ^ Part of the electromagnetic spectrum consists of the radio frequency spectrum and the optical spectrum.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]
.Electromagnetic radiation with a wavelength between 380 nm and 760 nm (790–400 terahertz) is detected by the human eye and perceived as visible light.^ In the electromagnetic spectrum, long wavelengths correspond to the radio frequency spectrum, intermediate wavelengths to millimeter and infrared radiation, short wavelengths to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ Complete range of electromagnetic radiation, from very short-wavelength (high-frequency) gamma-rays, through X-rays and ultraviolet light to the small range of visible light, and further to infrared radiation, microwave, and the comparatively long-wavelength low-frequency radio waves.

 ^ Invisible, electromagnetic radiation beyond red light on the spectrum, with wavelengths greater than 0.7 microns.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 .Other wavelengths, especially near infrared (longer than 760 nm) and ultraviolet (shorter than 380 nm) are also sometimes referred to as light, especially when the visibility to humans is not relevant.^ In the electromagnetic spectrum, long wavelengths correspond to the radio frequency spectrum, intermediate wavelengths to millimeter and infrared radiation, short wavelengths to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ In a graph of the visible light spectrum the Helium laser registers as a single line or wavelength.
  • Light Spectrum and Color Temperature 15 September 2009 8:31 UTC www.thekrib.com [Source type: FILTERED WITH BAYES]

 ^ Quote: you'll note that microwaves are less potentially harmful to humans than infrared or visible light I do know that microwaves are non-ionizing radiation.
  • xkcd • View topic - "Electromagnetic Spectrum" Discussion 19 January 2010 18:018 UTC forums.xkcd.com [Source type: FILTERED WITH BAYES]
.If radiation having a frequency in the visible region of the EM spectrum reflects off of an object, say, a bowl of fruit, and then strikes our eyes, this results in our visual perception of the scene.^ But our concern in the present context is with electromagnetic radiation, of which the waves on the electromagnetic spectrum are a particularly significant example.

 ^ In the electromagnetic spectrum, long wavelengths correspond to the radio frequency spectrum, intermediate wavelengths to millimeter and infrared radiation, short wavelengths to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ At the furthest known reaches of the electromagnetic spectrum are gamma rays, ultra high-frequency, high-energy, and short-wavelength forms of radiation.

 .Our brain's visual system processes the multitude of reflected frequencies into different shades and hues, and through this not-entirely-understood psychophysical phenomenon, most people perceive a bowl of fruit.^ Until approximately 60 years ago, our knowledge of the universe outside of the Earth came almost entirely from visual, optical astronomical observations.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ The organization of the electromagnetic spectrum's radio frequencies—which, of course, is an entirely arbitrary, humanmade process—is fascinating.

 ^ Not only did FM offer a different type of modulation; it was on an entirely different frequency range.
.At most wavelengths, however, the information carried by electromagnetic radiation is not directly detected by human senses.^ Invisible, electromagnetic radiation beyond red light on the spectrum, with wavelengths greater than 0.7 microns.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 ^ In the electromagnetic spectrum, long wavelengths correspond to the radio frequency spectrum, intermediate wavelengths to millimeter and infrared radiation, short wavelengths to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ At the furthest known reaches of the electromagnetic spectrum are gamma rays, ultra high-frequency, high-energy, and short-wavelength forms of radiation.

 .Natural sources produce EM radiation across the spectrum, and our technology can also manipulate a broad range of wavelengths.^ But our concern in the present context is with electromagnetic radiation, of which the waves on the electromagnetic spectrum are a particularly significant example.

 ^ At the furthest known reaches of the electromagnetic spectrum are gamma rays, ultra high-frequency, high-energy, and short-wavelength forms of radiation.

 ^ The electromagnetic spectrum is the complete range of electromagnetic waves on a continuous distribution from a very low range of frequencies and energy levels, with a correspondingly long wavelength, to a very high range of frequencies and energy levels, with a correspondingly short wavelength.

 .Optical fiber transmits light which, although not suitable for direct viewing, can carry data that can be translated into sound or an image.^ This is the job of the packet layer, which will split the data into small “packets.” 6.2 Packet Layer The packet layer is a layer of abstraction that separates the data being transmitted from the way that it is being transmitted.
  • 4 G Wireless Systems 19 January 2010 18:018 UTC www.myplick.com [Source type: FILTERED WITH BAYES]

 ^ Periodic waves are divided into longitudinal and transverse waves, the latter (of which light waves are an example) being waves in which the vibration or motion is perpendicular to the direction in which the wave is moving.

 .The coding used in such data is similar to that used with radio waves.^ This figure is for radio waves of extremely low frequency; ordinary radio waves of the kind used for actual radio broadcasts are closer to 10 5 centimeters (about 328 ft).

 ^ Radio waves can be used to send communication signals, or even to cook food; they can also be used to find and measure things.

 ^ Though the work of Maxwell and Hertz was foundational to the harnessing of radio waves for human use, the practical use of radio had its beginnings with Marconi.

Ultraviolet light

Main article: Ultraviolet
The amount of penetration of UV relative to altitude in Earth's ozone
.Next in frequency comes ultraviolet (UV).^ Next in frequency comes ultraviolet (UV).
  • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

 ^ Next comes ultraviolet.
  • Chemistry - Electromagnetic spectrum 19 January 2010 18:018 UTC www.chemistrydaily.com [Source type: Reference]

 ^ The super high frequency ( SHF ) and extremely high frequency ( EHF ) of microwaves come next up the frequency scale.
  • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

 .This is radiation whose wavelength is shorter than the violet end of the visible spectrum, and longer than that of an x-ray.^ The invisible rays of the spectrum that are outside of the visible spectrum at its short-wavelength violet end.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 ^ Invisible, electromagnetic radiation beyond red light on the spectrum, with wavelengths greater than 0.7 microns.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 ^ In a graph of the visible light spectrum the Helium laser registers as a single line or wavelength.
  • Light Spectrum and Color Temperature 15 September 2009 8:31 UTC www.thekrib.com [Source type: FILTERED WITH BAYES]
.Being very energetic, UV can break chemical bonds, making molecules unusually reactive or ionizing them (see photoelectric effect), in general changing their mutual behavior.^ I've tried that,to me it seemed like it would be that apart from objects being changed by change inflicted immediately in the area it would also be affected by change inflicted in that part of space in general.
  • There are some things that we just can't imagine. 19 January 2010 18:018 UTC www.escapistmagazine.com [Source type: Original source]

 ^ By the time of Hertz, wave theory had become dominant; but the photoelectric effect also exhibited aspects of particle behavior.

 .Sunburn, for example, is caused by the disruptive effects of UV radiation on skin cells, which is the main cause of skin cancer, if the radiation irreparably damages the complex DNA molecules in the cells (UV radiation is a proven mutagen).^ Sagripanti JL, Swicord ML, and Davis CC, Microwave effects on plasmid DNA, Radiation Research 110, pp.
  • Electromagnetic Radiation - Free Article 19 January 2010 18:018 UTC www.latitudes.org [Source type: FILTERED WITH BAYES]

 ^ Though its effects on Earth were negligible, instruments aboard several satellites provided data concerning an enormous quantity of radiation caused by gamma rays.

 ^ Sagripanti JL, and Swicord ML, DNA structural changes caused by microwave radiation, Int J Radiat Biol , 50(1), pp.
  • Electromagnetic Radiation - Free Article 19 January 2010 18:018 UTC www.latitudes.org [Source type: FILTERED WITH BAYES]

 .The Sun emits a large amount of UV radiation, which could quickly turn Earth into a barren desert.^ In a microwave oven, microwaves emitted by a small antenna are directed into the cooking compartment, and as they enter, they pass a set of turning metal fan blades.

 ^ Due to the fact that Earth is largely opaque, or resistant, to ultraviolet light, the most significant technological applications of UV radiation are found in outer space.

 ^ Very little of the Sun's ultraviolet light penetrates Earth's atmosphere—a fortunate thing, since ultraviolet (UV) radiation can be very harmful to human skin.

 However, most of it is absorbed by the atmosphere's ozone layer before reaching the surface.

X-rays

Main article: X-rays
.After UV come X-rays, which are also ionizing, but due to their higher energies they can also interact with matter by means of the Compton effect.^ The combined effect means a tube must spread energy outside the human response curve for best plant growth, usually.
  • Light Spectrum and Color Temperature 15 September 2009 8:31 UTC www.thekrib.com [Source type: FILTERED WITH BAYES]

 Hard X-rays have shorter wavelengths than soft X-rays. .As they can pass through most substances, X-rays can be used to 'see through' objects, most notably diagnostic x-ray images in medicine (a process known as radiography), as well as for high-energy physics and astronomy.^ UWB uses all frequencies from high to low, thereby passing through objects like the sea or layers of rock.
  • 4 G Wireless Systems 19 January 2010 18:018 UTC www.myplick.com [Source type: FILTERED WITH BAYES]

 ^ The optical and radio windows are important because they allow these electromagnetic waves to pass through the atmosphere and be received on the Earth's surface.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ At the furthest known reaches of the electromagnetic spectrum are gamma rays, ultra high-frequency, high-energy, and short-wavelength forms of radiation.

 .Neutron stars and accretion disks around black holes emit X-rays, which enable us to study them.^ [A84] (b) The surface surrounding a black hole with the property that any light ray emitted inside it cannot escape because of the strength of the gravitational field.

 .X-rays are given off by stars, and strongly by some types of nebulae.^ Some astronomers speculate that the source of these gamma-ray bursts may ultimately be a distant supernova, or exploding star.

Gamma rays

Main article: Gamma rays
.After hard X-rays come gamma rays, which were discovered by Paul Villard in 1900. These are the most energetic photons, having no defined lower limit to their wavelength.^ In the electromagnetic spectrum, long wavelengths correspond to the radio frequency spectrum, intermediate wavelengths to millimeter and infrared radiation, short wavelengths to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ At the furthest known reaches of the electromagnetic spectrum are gamma rays, ultra high-frequency, high-energy, and short-wavelength forms of radiation.

 ^ The ultra-short wavelengths of gamma rays, after all, are equal to one-trillionth of a centimeter.

 .They are useful to astronomers in the study of high energy objects or regions, and find a use with physicists thanks to their penetrative ability and their production from radioisotopes.^ UWB uses all frequencies from high to low, thereby passing through objects like the sea or layers of rock.
  • 4 G Wireless Systems 19 January 2010 18:018 UTC www.myplick.com [Source type: FILTERED WITH BAYES]

 ^ "This could affect their mood and ability to learn in the classroom if they have been using a phone during break time, for instance.
  • Electromagnetic Radiation - Free Article 19 January 2010 18:018 UTC www.latitudes.org [Source type: FILTERED WITH BAYES]

 ^ Numerous astronomical techniques were used for many environmental applications ranging from the study of ozone depletion, the design of fusion reactors, and to the study of global climatic changes.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 .Gamma rays are also used for the irradiation of food and seed for sterilization, and in medicine they are used in radiation cancer therapy and some kinds of diagnostic imaging such as PET scans.^ Despite these potential hazards, some authors have reported the use of MR imaging to control the depth of electrode implantation.
  • Neuroimaging and Deep Brain Stimulation -- Dormont et al. 31 (1): 15 -- American Journal of Neuroradiology 19 January 2010 18:018 UTC www.ajnr.org [Source type: Academic]

 ^ They will be using mobile phones for longer, and their effects won't be known for some time to come.
  • Electromagnetic Radiation - Free Article 19 January 2010 18:018 UTC www.latitudes.org [Source type: FILTERED WITH BAYES]

 ^ A child's immune system, whose efficiency is, in any case, degraded by radiation of the kind used in mobile telephony, is generally less robust than is that of an adult, so that the child less able to cope with any adverse health effect provoked by (chronic) exposure to such radiation."
  • Electromagnetic Radiation - Free Article 19 January 2010 18:018 UTC www.latitudes.org [Source type: FILTERED WITH BAYES]

 .The wavelength of gamma rays can be measured with high accuracy by means of Compton scattering.^ The wavelength of gamma rays can be measured with high accuracy by means of Compton scattering .
  • Electromagnetic Spectrum encyclopedia topics | Reference.com 19 January 2010 18:018 UTC www.reference.com [Source type: FILTERED WITH BAYES]

 ^ At the furthest known reaches of the electromagnetic spectrum are gamma rays, ultra high-frequency, high-energy, and short-wavelength forms of radiation.

 ^ Gamma Rays were found to be very short wave radiation, more penetrating and of shorter wavelength than even X-Rays.
  • KryssTal : The Electromagnetic Spectrum 19 January 2010 18:018 UTC www.krysstal.com [Source type: FILTERED WITH BAYES]
.Note that there are no precisely defined boundaries between the bands of the electromagnetic spectrum.^ Between about 10 13 and 10 17 Hz on the electromagnetic spectrum is the range of light: infrared, visible, and ultraviolet.

 ^ Note that apart from the "daylight" and Aquarele, there > is no reference to anything as "blue" as 5,000 Kelvin.
  • Light Spectrum and Color Temperature 15 September 2009 8:31 UTC www.thekrib.com [Source type: FILTERED WITH BAYES]

 ^ Since the beginning of the twentieth century, uses for other bands in the electromagnetic spectrum have proliferated.

 .Radiation of some types have a mixture of the properties of those in two regions of the spectrum.^ A sodium-vapor street light is an example of the second law where the high-temperature, low-pressure sodium gas radiates two strong emission lines in the yellow-orange region of the spectrum.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ A typical type of low-E coating is transparent to the solar spectrum (visible light and short-wave infrared radiation) and reflective of long-wave infrared radiation.
  • The Efficient Windows Collaborative: Resources 19 January 2010 18:018 UTC www.efficientwindows.org [Source type: FILTERED WITH BAYES]

 .For example, red light resembles infrared radiation in that it can resonate some chemical bonds.^ Some animals can see infrared radiation!
  • There are some things that we just can't imagine. 19 January 2010 18:018 UTC www.escapistmagazine.com [Source type: Original source]

 ^ In the electromagnetic spectrum, long wavelengths correspond to the radio frequency spectrum, intermediate wavelengths to millimeter and infrared radiation, short wavelengths to visible and ultraviolet light, and extremely short wavelengths to x-rays and gamma rays.
  • NTIA Special Publication 98-35, Radio Astronomy Spectrum Planning Options, Chapter 1 19 January 2010 18:018 UTC www.ntia.doc.gov [Source type: FILTERED WITH BAYES]

 ^ Infrared light lies just below visible light in frequency, and this is easy to remember because of the name: red is the lowest in frequency of all the colors.

See also

Electronics portal

References

  1. ^ "Imagine the Universe! Dictionary". http://imagine.gsfc.nasa.gov/docs/dict_ei.html#em_spectrum. 
  2. ^ What is Light? – UC Davis lecture slides
  3. ^ The Electromagnetic Spectrum, The Physics Hypertextbook
  4. ^ Definition of frequency bands on vlf.it
  5. ^ Mohr, Peter J.; Taylor, Barry N.; Newell, David B. (2008). "CODATA Recommended Values of the Fundamental Physical Constants: 2006". Rev. Mod. Phys. 80: 633–730. doi:10.1103/RevModPhys.80.633. http://physics.nist.gov/cuu/Constants/codata.pdf.  Direct link to value.
  6. ^ J. J. Condon and S. M. Ransom. "Essential Radio Astronomy: Pulsar Properties". National Radio Astronomy Observatory. http://www.cv.nrao.edu/course/astr534/Pulsars.html. Retrieved 2008-01-05. 
  7. ^ A. A. Abdo; B. Allen; D. Berley; E. Blaufuss; S. Casanova; C. Chen; D. G. Coyne; R. S. Delay; B. L. Dingus; R. W. Ellsworth; L. Fleysher; R. Fleysher; I. Gebauer; M. M. Gonzalez; J. A. Goodman; E. Hays; C. M. Hoffman; B. E. Kolterman; L. A. Kelley; C. P. Lansdell; J. T. Linnemann; J. E. Mc Enery; A. I. Mincer; I. V. Moskalenko; P. Nemethy; D. Noyes; J. M. Ryan&#x A;;&#x A; F. W. Samuelson&#x A;;&#x A; P. M. Saz Parkinson; M. Schneider; A. Shoup&#x A;;&#x A; G. Sinnis&#x A;;&#x A; A. J. Smith; A. W. Strong; G. W. Sullivan; V. Vasileiou; G. P. Walker; D. A. Williams; X. W. Xu; G. B. Yodh (2007-03-20). "Discovery of TeV Gamma‐Ray Emission from the Cygnus Region of the Galaxy". The Astrophysical Journal Letters 658: L33. doi:10.1086/513696. 
  8. ^ CORRECTIONS TO MUONIC X-RAYS AND A POSSIBLE PROTON HALO slac-pub-0335 (1967)
  9. ^ Hyperphysics (see Gamma-Rays

External links

Electromagnetic spectrum
← shorter wavelengths       longer wavelengths →
Gamma rays · X-rays · Ultraviolet · Visible · Infrared · Terahertz radiation · Microwave · Radio
Visible (optical)
Violet · Blue · Green · Yellow · Orange · Red
Microwaves
W band · V band · Q band · Ka band · K band · Ku band · X band · S band · C band · L band
Radio
EHF · SHF · UHF · VHF · HF · MF · LF · VLF · ULF · SLF · ELF
Wavelength types

Simple English

The electromagnetic (EM) spectrum is the range of all possible electromagnetic radiation. Electromagnetic radiation can be divided into octaves — as sound waves are — winding up with eighty-one octaves.[1] The "electromagnetic spectrum" (usually just spectrum) of an object is the frequency range of electromagnetic radiation with wavelengths from thousands of kilometres down to fractions of the size of an atom.

It is commonly said that EM waves beyond these limits are uncommon, although this is not actually true. The short wavelength limit is likely to be the Planck length, and the long wavelength limit is the size of the universe itself, though in principle the spectrum is infinite.

Spectra of objects

Nearly all objects in the universe emit, reflect or transmit some light. (One hypothetical exception may be dark matter.) The distribution of this light along the electromagnetic spectrum (called the spectrum of the object) is determined by the object's composition. Several types of spectra can be distinguished depending upon the nature of the radiation coming from an object.

Electromagnetic spectroscopy is the branch of physics that deals with the characterization of matter by its spectra.

NOTE: The AUDIO entry in this graphic is there for comparison only. Sound waves and light are two different things entirely.

References

  1. ↑ Isaac Asimov, Isaac Asimov's Book of Facts. Hastingshouse/Daytrips Publ., 1992. Page 389.

Other websites

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