6. Electromagnetic waves

2018 ◽  
pp. 70-99
Author(s):  
Mike Goldsmith
Keyword(s):  
Electromagnetic Radiation ◽  
Infrared Radiation ◽  
Electromagnetic Waves ◽  
Scientific Investigation ◽  
The Other ◽  
Electromagnetic Spectrum ◽  
X Rays ◽  
Radio Waves ◽  
History Of ◽  
Insight Into

‘Electromagnetic waves’ considers the history of the scientific investigation into the electromagnetic spectrum, including Einstein’s insight into the quantized nature of electromagnetic radiation. It explains that the only difference between light, radio waves, and all the other forms of electromagnetic radiation is the length of the fictitious-but-convenient waves or, equivalently, the energy of the photons involved. These different energies lead to different mechanisms for the formation and absorption of the different kinds of radiation, and it is this which gives rise to their different behaviours. Radio waves, microwaves, infrared radiation, light, ultraviolet light, X-rays, and gamma rays are all discussed.

4. Windows in the sky

2016 ◽  
pp. 39-46
Author(s):  
Geoff Cottrell
Keyword(s):  
Solar Radiation ◽  
Electromagnetic Radiation ◽  
Electromagnetic Waves ◽  
Outer Space ◽  
Cosmic Ray ◽  
High Energy ◽  
Electromagnetic Spectrum ◽  
Radio Waves ◽  
Transverse Waves ◽  
The Universe

The atmosphere influences much of what can be seen through a telescope. Most of the atmosphere lies within 16 km from the Earth’s surface. Further out, the air becomes thinner until it merges with outer space. In the ionosphere—a layer 75–1000 km high—neutral atoms are ionized by solar radiation and high-energy cosmic ray particles arriving from distant parts of the Universe. ‘Windows in the sky’ explains electromagnetic radiation and the electromagnetic spectrum from gamma rays through to visible light and radio waves. Electromagnetic waves are transverse waves that can be polarized. The atmosphere acts as a filter and blocks cosmic electromagnetic radiation. Atmospheric turbulence distorts starlight resulting in ‘twinkling’ stars.

Principles of Microwave Radiation

1980 ◽  
Vol 43 (8) ◽  
pp. 618-624 ◽  
Author(s):  
B. CURNUTTE
Keyword(s):  
Electromagnetic Radiation ◽  
Microwave Radiation ◽  
Food Processing ◽  
Electromagnetic Waves ◽  
Ultra Violet ◽  
X Rays ◽  
Radio Waves ◽  
Dual Nature ◽  
Ultra Violet Radiation ◽  
Transmission And Absorption

Microwaves, such as those used in cooking and processing food, are part of the broad spectrum of electromagnetic radiation which includes radio waves, microwaves, infrared radiation, visible light, ultra-violet radiation, x-rays and Gamma rays. Electromagnetic radiation has a dual nature, it is both wave-like and particle-like. An understanding of this dual nature of electromagnetic radiation is necessary for an understanding of the processes of emission, transmission and absorption of microwaves, which is in turn necessary for understanding the processes and phenomena which are important in the use of microwave radiation as a source of energy for heating and food processing. The properties of electromagnetic waves and the processes of emission. transmission and absorption are described and some effects in microwave-heating applications are discussed.

scholarly journals High Redshift Radio Galaxies

1996 ◽  
Vol 175 ◽  
pp. 571-576
Author(s):  
K. Meisenheimer ◽  
H. Hippelein ◽  
M. Neeser
Keyword(s):  
Radio Emission ◽  
Electromagnetic Waves ◽  
High Redshift ◽  
Radio Galaxies ◽  
Early History ◽  
Radio Telescopes ◽  
Radio Waves ◽  
History Of ◽  
The Universe ◽  
Travel Distances

One hundred years after G. Marconi recorded radio waves over a distance of more than 1000 m, the most sensitive radio telescopes are able to detect the radio emission from light travel distances at least 1.4 × 1023 times greater. The electromagnetic waves from these distant objects are red shifted by Δλ/λ = z > 4. It is not the mere distance of high redshift objects which is fascinating, but rather the fact that one looks back into the early history of the universe by observing them: Objects at a redshift of 4 shined at a time when the universe had reached only about 1/5 of its present age.

scholarly journals The complement component C4 of mammals

1990 ◽  
Vol 265 (2) ◽  
pp. 495-502 ◽  
Author(s):  
A W Dodds ◽  
S K A Law
Keyword(s):  
Mammalian Species ◽  
Covalent Binding ◽  
Complement Component ◽  
The Other ◽  
Class Iii ◽  
Duplication Events ◽  
History Of ◽  
Limited Protein ◽  
Tandem Genes ◽  
Insight Into

Human complement component C4 is coded by tandem genes located in the HLA class III region. The products of the two genes, C4A and C4B, are different in their activity. This difference is due to a degree of ‘substrate’ specificity in the covalent binding reactions of the two isotypes. Mouse also has a duplicated locus, but only one gene produces active C4, while the other codes for the closely related sex-limited protein (Slp). In order to gain some insight into the evolutionary history of the duplicated C4 locus, we have purified C4 from a number of other mammalian species, and tested their binding specificities. Like man, chimpanzee and rhesus monkey appear to produce two C4 types with reactivities similar to C4A and C4B. Rat, guinea pig, whale, rabbit, dog and pig each expresses C4 with a single binding specificity, which is C4B-like. Sheep and cattle express two C4 types, one C4B-like, the other C4A-like, in their binding properties. These results suggest that more than one locus may be present in these species. If this is so, then the duplication of the C4 locus is either very ancient, having occurred before the divergence of the modern mammals, or there have been three separate duplication events in the lines leading to the primates, rodents and ungulates.

William H. Bragg's Corpuscular Theory of X-Rays and γ-Rays

1971 ◽  
Vol 5 (3) ◽  
pp. 258-281 ◽  
Author(s):  
Roger H. Stuewer
Keyword(s):  
Ultra Violet ◽  
Black Body ◽  
Black Body Radiation ◽  
Electromagnetic Spectrum ◽  
Light Quantum ◽  
X Rays ◽  
Ultra Violet Light ◽  
Violet Light ◽  
History Of ◽  
Γ Rays

The modern corpuscular theory of radiation was born in 1905 when Einstein advanced his light quantum hypothesis; and the steps by which Einstein's hypothesis, after years of profound scepticism, was finally and fully vindicated by Arthur Compton's 1922 scattering experiments constitutes one of the most stimulating chapters in the history of recent physics. To begin to appreciate the complexity of this chapter, however, it is only necessary to emphasize an elementary but very significant point, namely, that while Einstein based his arguments for quanta largely on the behaviour of high-frequency black body radiation or ultra-violet light, Compton experimented with X-rays. A modern physicist accustomed to picturing ultra-violet light and X-radiation as simply two adjacent regions in the electromagnetic spectrum might regard this distinction as hair-splitting. But who in 1905 was sure that X-rays and γ-rays are far more closely related to ultra-violet light than to α-particles, for example ? This only became evident after years of painstaking research, so that moving without elaboration from Einstein's hypothesis to Compton's experiments automatically eliminates from consideration an important segment of history—a segment in which a major role was played by William Henry Bragg.

scholarly journals GODS AND GHOST-LIGHT: ANCIENT EGYPT, ELECTRICITY, AND X-RAYS

2017 ◽  
Vol 45 (1) ◽  
pp. 119-135 ◽  
Author(s):  
Eleanor Dobson
Keyword(s):  
Ancient Egypt ◽  
Turn Of The Century ◽  
Electromagnetic Spectrum ◽  
X Rays ◽  
Radio Waves ◽  
Psychical Research ◽  
Cerebral Ganglia ◽  
Society For Psychical Research ◽  
The Brain ◽  
Infinite Range

In 1892 the celebrated physicistand chemist William Crookes commented on the existence of “an almost infinite range of ethereal vibrations or electrical rays,” which he believed could revolutionize telegraphic communications (174). A few years later, and aided by Crookes's experiments with vacuums, the German physicist Wilhelm Röntgen successfully produced X-rays, a hitherto unrecorded form of electromagnetic radiation, which he tantalizingly described as “a new kind of invisible light” (Röntgen 413; Warner 256). Crookes was quick to speculate as to “the possibility of links between roentgen rays and the cerebral ganglia,” that an undiscovered organ in the brain might be “capable of transmitting and receiving . . . electrical rays” (Lyons 105; Crookes 176). X-rays, he thought, might prove a psychic counterpart to higher wavelength radio waves, allowing the transmission of messages telepathically rather than telegraphically, and even communication with the world of the spirits (Lyons 105). Crookes theorized that the parapsychological was intimately entwined with the findings of contemporary physics, occupying different zones of the same electromagnetic spectrum. An ardent Spiritualist, he believed that the ether, the “impalpable, invisible entity, by which all space is supposed to be filled” and which contained countless “channels of communication” also sustained “ghost-light . . . invisible to the naked eye” and acted as a medium that allowed “ethereal bodies to rise up” (Crookes 174; Warner 253–56). In other words, the matter through which light and electrical signals passed was envisaged as the same substance which allowed the spirits to fluctuate between visible and invisible forms. These links between the electromagnetic field and the occult, endorsed by Crookes and certain other members of his circles such as the Society for Psychical Research, anticipated turn-of-the-century associations between electricity, radiation and ancient Egypt which, through its reputation as the birthplace of magic, was central to Victorian conceptions of the supernatural.

Structure of the Atom

2009 ◽  
Author(s):  
Christopher O. Oriakhi
Keyword(s):  
Electronic Structure ◽  
Electromagnetic Radiation ◽  
Characteristic Frequency ◽  
Wave Number ◽  
X Rays ◽  
Radio Waves ◽  
Light Wavelength ◽  
Speed Of Light ◽  
Continuous Stream ◽  
Unit Of Length

The arrangement of electrons around the nucleus of an atom is known as its electronic structure. Since electrons determine all the chemical and most physical properties of an atomic system, it is important to understand the electronic structure. Much of our understanding has come from spectroscopy, the analysis of the light absorbed or emitted by a substance. Electromagnetic radiation is a form of energy; light is the most familiar type of electromagnetic radiation. But radio waves, microwaves, X-rays, and many other similar phenomena are also types of electromagnetic radiation. All these exhibit wavelike properties, and all travel through a vacuum at the speed of light. The wavelike propagation of electromagnetic radiation can be described by its frequency (ν), wavelength (λ), and speed (c). Wavelength (lambda, λ): The wavelength of a wave is the distance between two successive peaks or troughs. Frequency (nu, ν): The frequency of a wave is the number of waves (or cycles) that pass a given point in space in one second. The unit is expressed as the reciprocal of seconds (s−1) or as hertz (Hz). A hertz is one cycle per second (1 Hz = 1 s−1). Speed of light (c): The speed of light in a vacuum is one of the fundamental constants of nature, and does not vary with the wavelength. It has a numerical value of 2.9979 × 108 m/s, but for convenience we use 3.0 × 108 m/s. These measurements are related by the equation: Speed of light =Wavelength×Frequency c = λν This expression can be rearranged to give: λ = c/v, or ν = c/λ Wave number (⊽): The wave number is a characteristic of a wave that is proportional to energy. It is defined as the number of wavelengths per unit of length (usually in centimeter, cm).Wave number may be expressed as ⊽ =1/λ While electromagnetic radiation behaves like a wave, with characteristic frequency and wavelength, experiment has shown that electromagnetic radiation also behaves as a continuous stream of particles or energy packets.

scholarly journals The Science Potential of Far-IR/Sub-mm Interferometry and Concepts for the SPIRIT and SPECS Missions

2001 ◽  
Vol 205 ◽  
pp. 438-439
Author(s):  
David Leisawitz ◽  
Keyword(s):  
Galaxy Evolution ◽  
Background Radiation ◽  
Large Population ◽  
Far Infrared ◽  
Electromagnetic Spectrum ◽  
History Of ◽  
Evolution Of Structure ◽  
Optical Surveys ◽  
The Universe ◽  
Insight Into

The FIR/SMM region is unique in the electromagnetic spectrum in its potential for vast increases in sensitivity and angular resolution, and, as a result, information vital to our understanding of the evolution of structure in the universe. About half of the luminosity in the universe is emitted in the far infrared. Evidence for this can be found both in the spectra of individual galaxies (Trentham et al. 1999) and in the cosmic FIR/SMM background found by COBE (Hauser et al. 1998; Fixsen et al. 1998; Dwek et al. 1998). JCMT/SCUBA observations suggest that “a large population of luminous, strongly obscured sources at redshifts ≲5 is missing from optical surveys” and could account for the background radiation (Blain et al. 1999). Future FIR/SMM measurements of these sources have the potential to reveal the luminosity history of the universe and will provide insight into the processes of galaxy and star formation and galaxy evolution.

Perichoresis: New Theological Wine in an Old Theological Wineskin

Horizons ◽  
1995 ◽  
Vol 22 (1) ◽  
pp. 49-66 ◽  
Author(s):  
Michael G. Lawler
Keyword(s):  
The Other ◽  
History Of ◽  
History Of Theology ◽  
The One ◽  
Insight Into ◽  
Theological Concept

AbstractThe history of theology demonstrates that theological exploration, seeking to understand fully an already given theological concept, regularly brings forth unexpected insights. This article seeks to do just that. Reflecting on an ancient theological word, perichoresis, coined in its original Greek to express the intimate communion of, first, the two natures in the one person of Jesus and, second, the three persons in one God, the article seeks new theological insight into the communion that is essential in, first, Christian marriage and then, church. The analysis underscores communion-through-perichoresis as essential to the definitions of God, marriage, and church, and relates the three one to the other.

scholarly journals REVIEW OF THE INFLUENCE OF ELECTROMAGNETIC RADIATIONS OF DIFFERENT RANGE ON THE PHYSIOLOGICAL PROCESSES OF HUMAN AND ANIMAL SPERMATOZOA

2021 ◽  
pp. 42-54
Author(s):  
D.V. Zadubenko ◽  
D.N. Sultanova ◽  
M.I. Pak ◽  
I.M. Kim ◽  
E.К. Kilina ◽  
...  
Keyword(s):  
Electromagnetic Radiation ◽  
Experimental Studies ◽  
Reproductive Function ◽  
X Rays ◽  
Radio Waves ◽  
Biochemical Processes ◽  
Male Reproductive Function ◽  
Physiological Processes ◽  
Negative Effect

This review presents 40 experimental studies of the effect of electromagnetic radiation of various ranges on the male reproductive function of humans and other vertebrates. The review includes works performed in the period from 2010 to 2020. Currently, not only the negative effect of radio waves, X-rays and gamma radiation has been shown, but many experiments have been carried out, where with the help of electromagnetic radiation it is possible to favorably influence spermatogenesis in general and physiological, biochemical processes in spermatozoa in particular. The purpose of this bibliographic study was to search for options for exposure to electromagnetic radiation to modulate the biological processes of spermatogenesis and sperm motility in vitro.

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