electromagnetic spectrum

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electromagnetic spectrum

See electromagnetic radiation.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

electromagnetic spectrum

[i¦lek·trō·mag′ned·ik ′spek·trəm]
The total range of wavelengths or frequencies of electromagnetic radiation, extending from the longest radio waves to the shortest known cosmic rays.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

electromagnetic spectrum

electromagnetic spectrumclick for a larger image
electromagnetic spectrumclick for a larger image
electromagnetic spectrumclick for a larger image
electromagnetic spectrumclick for a larger image
The ordered array of known electromagnetic radiation, extending from the shortest cosmic rays, through gamma rays, X-rays, ultraviolet radiation, visible radiation, and infrared radiation. It includes microwave and all other wavelengths of radio energy. See the illustration for a more detailed view of this spectrum.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved


The range of electromagnetic radiation (electromagnetic waves) in our known universe, which includes visible light. The radio spectrum, which includes both licensed and unlicensed frequencies up to 300 GHz has been defined worldwide in three regions: Europe and Northern Asia (Region 1); North and South America (Region 2), and Southern Asia and Australia (Region 3). Some frequency bands are used for the same purpose in all three regions while others differ. See satellite frequency bands and optical bands.

Higher Frequencies
Frequencies above 40 GHz have not been licensed, but are expected to be made available in the future as the technology is developed to transmit at these smaller wavelengths (higher frequencies). The spectrum can be viewed in meticulous detail from the Federal Communications Commission (FCC) and National Telecommunications and Information Administration (NTIA) by visiting www.fcc.gov/oet/spectrum and www.ntia.doc.gov/osmhome/osmhome.html. See electromagnetic radiation and wave.

Should Airwaves Be Licensed?

There is a great deal of controversy over the licensing of frequencies. In Kevin Werbach's very educational white paper, "Radio Revolution," the author says an artificial scarcity has been created because policy makers do not understand the technology. He states that many believe the traditional policy of dividing the airwaves into licensed bands now impedes progress because today's radio technologies allow for much more sharing of the spectrum than ever before. The old notion that radio waves interfere with and cancel each other is a false one. Waves just mix together and become more difficult to differentiate, but modern electronics can, in fact, separate them.

To obtain a copy of this insightful report written in 2003, as well as other related articles, visit Werbach's website at www.werbach.com. See smart radio.

Visible Light
Our eyes perceive a tiny sliver of the electromagnetic spectrum. The wavelengths from (approximately) 400 to 750 nanometers provide us with our physical view of the universe.

Visible Light
Our eyes perceive a tiny sliver of the electromagnetic spectrum. The wavelengths from (approximately) 400 to 750 nanometers provide us with our physical view of the universe.
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References in periodicals archive ?
This indicates that the N1-N2 bond became stronger, in parallel with the data obtained in the IR in which the v(N-N) underwent positive shift in the IR spectrum of the complex.
The IR spectrum showed a broad peak at 3700-2500 [cm.sup.-1] attributable to hydrogen-bonded hydroxylic group.
The IR spectrum (not shown) of the sample corresponding to the [R.sub.f] 0.90 spot was similar to that of the whole sample, while the sample corresponding to the trailing spot had a relatively high alkyl content, in addition to some aromatic species.
The IR spectrum reveals the presence of polytetrafluoroethylene, also known as Teflon.
An IR spectrum of a nylon-rayon mixture was used as a search query against an IR spectral database.
Because the endoscopic samples are small and it is hard to obtain a high-quality IR spectrum, a modified attenuated total reflectance (ATR) accessory was linked to a WQD500 FT-IR spectrometer (Beijing No.
In sample preparations for recording the FT IR spectrum, the samples of paper or prints were weighted, from 1,0 mg and 150,0 mg KBr in powder form.
FTIR detection in used in areas where the complementary information from an IR spectrum is necessary, The largest market for our turnkey IRD detector is the forensics market where complementary identification of illicit drugs in necessary, It is also an important analytical tool for competitive formulation analysis, identification and characterization of organic synthesis products and by-products, regulatory compliance, drug metabolic studies, environmental analysis, flavors and fragrances, food product analysis, and petroleum and fuels
The IR spectrum of the 50.0% reference standard is shown in Figure 1A.
The IR spectrum is commonly called the "fingerprint" region because in it most organic molecules exhibit a large number of well-defined peaks.
[H.sub.2] is also a probable irradiation product, although it does not show up in the IR spectrum. Both saturated and unsaturated organics seem to appear at reduced levels, although it is possible that they may arise as the result of subsequent gas phase chemistry in the closed system.