electromagnetic radiation pdf


<>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 595.32 841.92] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Depending on the frequency, there are two categories of EMF: ionising and nonionising- radiation (see Figure 1). The article also traces the development of both the classical and quantum theories of radiation. his chapter is a review of the classical or wave nature of electromagnetic (EM) radiation; it is assumed that the reader is familiar with some of this material. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. A useful relation for quick calculations is that light travels about 1 ft per nanosecond (10-9 s). 3.1 Non-ionizing radiation . stream The basic properties and behaviour of electromagnetic radiation are discussed in this article, as are its various forms, including their sources, distinguishing characteristics, and practical applications. 19 3.7 The ICNIRP guidelines apply only to short-term exposure. Electromagnetic fields (EMF) are invisible areas of energy, 7 measured in hertz (Hz). All human life is immersed in it, and modern communications technology and medical services are particularly dependent on one or another of its forms. Diagram of photosynthesis showing how water, light, and carbon dioxide are absorbed by a plant to produce oxygen, sugars, and more carbon dioxide. Electromagnetic Radiation (EMR) Clashes With Honey Bees Sainudeen Sahib.S International Journal of Enviro nmental Sciences Volume 1 No.5, 2011 900 All mobile phone towers emit microwave radiations, which is in the radio frequency radiation (RFR), part of the spectrum of electromagnetic waves. The magnetic and the electric fields come at 90° to each other and the combined waves move perpendicular to both electric and magnetic oscillating fields occurring the disturbance. Such is also true of X-rays, which are important in medicine as they allow physicians to observe the inner parts of the body but exposure to which should be kept to a minimum. endobj In terms of the modern quantum theory, electromagnetic radiation is the flow of photons (also called light quanta) through space. There are two forms of radiation – non-ionizing and ionizing – which will be discussed in sections 3.1 and 3.2, respectively. An electromagnetic wave is characterized by its intensity and the frequency ν of the time variation of the electric and magnetic fields. Electromagnetic radiation can be defined as a form of energy that is produced by the movement of electrically charged particles traveling through a matter or vacuum or by oscillating magnetic and electric disturbance. • Light travels through the vacuum of space – unlike sound. Close to 0.01 percent of the mass/energy of the entire universe occurs in the form of electromagnetic radiation. Title: Electromagnetic Radiation Author: Doug Created Date: 6/26/2003 8:11:46 PM Abstract—Radiofrequency electromagnetic fields (EMFs) are used to enable a number of modern devices, including mobile telecom-munications infrastructure and phones, Wi-Fi, and Bluetooth. time variations is such that l ≪ λthen the radiation … Electromagnetic Radiation Derivations The same could be done for an arbitrary kind or type of antenna (which means also for antenna types different to an isotropic antenna) by correcting the formula 3 by the antenna-gain g t: t t t i rt g r P S 4 ⋅ ⋅ 2 = ⋅ π (4 . GUIDELINES FOR LIMITING EXPOSURE TO ELECTROMAGNETIC FIELDS (100 kHz to 300 GHz) International Commission on Non-Ionizing Radiation Protection (ICNIRP) 1. The lesson focuses on radio waves to remind students of the concepts of frequency and wavelength, and ends with the speed of electromagnetic radiation, which is the same as the speed of light. Waves • Waves have 3 primary characteristics: • 1. Electromagnetic (EM) radiation is a form of energy that is all around us and takes many forms, such as radio waves, microwaves, X-rays and gamma rays. There is a spectrum of electromagnetic radiation with variable wavelengths and frequency, which in turn imparts different characteristics. At sufficiently high flux levels, various bands of electromagnetic radiation have been found to cause deleterious health effects in people.. Electromagnetic radiation can be classified into two types: ionizing radiation and non-ionizing radiation, based on the capability of a single photon with more than 10 eV energy to ionize atoms or break chemical bonds. Electromagnetic Radiation • Radiant energy that exhibits wavelength-like behavior and travels through space at the speed of light in a vacuum. Our editors will review what you’ve submitted and determine whether to revise the article. Figure 7.5: The electromagnetic spectrum. Photons are packets of energy hν that always move with the universal speed of light. This spectrum includes visible light, X-rays and radio waves. Everyday life is pervaded by artificially made electromagnetic radiation: food is heated in microwave ovens, airplanes are guided by radar waves, television sets receive electromagnetic waves transmitted by broadcasting stations, and infrared waves from heaters provide warmth. For simplicity we … Electromagnetic radiation can be useful as well as hazardous. Swapan Kumar Haldar, in Mineral Exploration (Second Edition), 2018. Practically all the fuels that modern society uses—gas, oil, and coal—are stored forms of energy received from the Sun as electromagnetic radiation millions of years ago. James Clerk Maxwell derived a wave form of the electric and magnetic equations, thus uncovering the wave-like nature of electric and magnetic fields and their symmetry. General Properties of all electromagnetic radiation Electromagnetic radiation can travel through empty space. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. Hence an oscillat-ing charge produces an electromagnetic field. Electromagnetic radiation exhibits a multitude of phenomena as it interacts with charged particles in atoms, molecules, and larger objects of matter. electromagnetic radiation (EMR) as an electromagnetic wave that travels through space at the speed of light, c,whichis3x108 meters per second (hereafter referred to as m s-1) or 186,282.03 miles s . 3.3.2.2 Electromagnetic Radiation. <> Louis Block Professor of Physics, University of Chicago. Green plants also have high sensitivity to the maximum intensity of solar electromagnetic radiation, which is absorbed by a substance called chlorophyll that is essential for plant growth via photosynthesis. 4 0 obj It covers a wide scope of practical topics, including medical treatment, telecommunication systems, and radiation effects. In such a wave, time-varying electric and magnetic fields are mutually linked with each other at right angles and perpendicular to the direction of motion. Radiation is energy in the form of waves of particles. 18 3.6 Why do reports of scientific studies often appear to reach different conclusions on EMF health effects? One of the most methodical treatments of electromagnetic wave propagation, radiation, and scattering—including new applications and ideas. In this timely book, the authors comprehensively treat two integrated aspects of electromagnetic radiation, theory and application. 102 Atmospheric Radiative Transfer-q +q x y z! The Scattering of Light and other Electromagnetic Radiation covers the theory of electromagnetic scattering and its practical applications to light scattering. These phenomena as well as the ways in which electromagnetic radiation is created and observed, the manner in which such radiation occurs in nature, and its technological uses depend on its frequency ν. Types of radiations in the electromagnetic spectrum include: radio waves, microwave, infrared, visible light, ultraviolet light, X-rays and gamma rays. Get exclusive access to content from our 1768 First Edition with your subscription. Electromagnetic radiation - Electromagnetic radiation - Properties and behaviour: If a charged particle interacts with an electromagnetic wave, it experiences a force proportional to the strength of the electric field and thus is forced to change its motion in accordance with the frequency of the electric field wave. Electromagnetic radiation is a form of energy that propagates as both electrical and magnetic waves traveling in packets of energy called photons. Electromagnetic Radiation Variational Methods, Waveguides, and Accelerators August 19, 2005 Springer Berlin Heidelberg NewYork HongKong London Milan Paris Tokyo. The application of electromagnetic radiation in modern life is one of the most developing technologies. Less familiar are gamma rays, which come from nuclear reactions and radioactive decay and are part of the harmful high-energy radiation of radioactive materials and nuclear weapons. It consists of both electric and magnetic field components. This book is divided into 10 chapters that particularly present examples of practical applications to light scattering from colloidal and macromolecular systems. PDF | On May 1, 2013, Norman Kerle published Electromagnetic Radiation (EMR) | Find, read and cite all the research you need on ResearchGate endobj Section6: Electromagnetic Radiation Potential formulation of Maxwell equations Now we consider a general solution of Maxwell’s equations. 3.5 Is electromagnetic hypersensitivity (EHS) caused by exposure to electromagnetic fields? Radiation is electromagnetic in nature, i.e., it consists of waves of electric and magnetic energy moving together through space at the speed of light. Electric and Magnetic Fields A changing electric field generates a changing magnetic field. <> The electromagnetic field is a physical field produced by electrically charged objects. Infrared waves also are given off and received by automatic self-focusing cameras that electronically measure and set the correct distance to the object to be photographed. Preface As soon as the Sun sets, incandescent or fluorescent lights are turned on to provide artificial illumination, and cities glow brightly with the colourful fluorescent and neon lamps of advertisement signs. Because the speed of EM waves predicted by the wave equation coincided with the measured speed of light, Maxwell concluded that light itself is an EM wave. Electromagnetic radiation is a phenomenon that takes the form of self-propagating energy waves as it travels through space (vacuum or matter). Wavelength: distance between two peaks in a wave. <>>> Non-ionizing radiation has less energy than ionizing radiation; it does not possess enough energy to . ) Maxwell's equations were confirmed by Heinrich Hertz through experiments with radio waves. x��[Yo��~`��')��W�10�=�I���$4ͱ�آW�v����:��!�x$6������:�t��p|�ڴ��o�>�M���%_�>�/������]����7��~}��|�)�������""�t����w"���H�,��N�Z�e�|~�~?��L���䞞*����w_6�����?��PL���Sr���M���*4�O���wyQ�UN�u�fy"tZ%e%�Z&-2��ss��ɷ}���Δ�2I�R2�e�U"2��н���&{f���Tei.�e�����N��Na��e��WͳT�y@T�2���ʷ���4+"��Nu1CV��rY�f฼ ���@G��0V�٘�#P��N�H�2�E�S���|�-�zR ��. Presented in two parts, this book takes an analytical approach on the subject and emphasizes new ideas and applications used today. Continuous spectra of electromagnetic radiation, Discrete-frequency sources and absorbers of electromagnetic radiation, Speed of electromagnetic radiation and the Doppler effect, Cosmic background electromagnetic radiation, Development of the classical radiation theory, Relation between electricity and magnetism, The electromagnetic wave and field concept, Development of the quantum theory of radiation, https://www.britannica.com/science/electromagnetic-radiation. As Each field has energy that comes from a … endobj Electromagnetic radiation is all around us. Electromagnetic radiation is self-sustaining energy with electric and magnetic field components. In fact, all living things on Earth depend on the electromagnetic radiation received from the Sun and on the transformation of solar energy by photosynthesis into plant life or by biosynthesis into zooplankton, the basic step in the food chain in oceans. The energy waves oscillate in phase perpendicular to each other and perpendicular to … The spectrum of frequencies of electromagnetic radiation extends from very low values over the range of radio waves, television waves, and microwaves to visible light and beyond to the substantially higher values of ultraviolet light, X-rays, and gamma rays. • Light travels as an electromagnetic wave. Ultraviolet light represents a kind of electromagnetic radiation that can be harmful to life. We dedicate this book to our wives, Margarita Ban˜os-Milton and Clarice Schwinger. Electromagnetic Radiation Last updated; Save as PDF Page ID 1779; Contributors and Attributions; As you read the print off this computer screen now, you are reading pages of fluctuating energy and magnetic fields. Wave Model of Electromagnetic Radiation. Let us know if you have suggestions to improve this article (requires login). The eyes of many animals, including those of humans, are adapted to be sensitive to and hence to see the most abundant part of the Sun’s electromagnetic radiation—namely, light, which comprises the visible portion of its wide range of frequencies. Photons having the same energy hν are all alike, and their number density corresponds to the intensity of the radiation. Electromagnetic radiation is commonly referred to as "light", EM, EMR, or electromagnetic waves. The radiation of electromagnetic waves can be explained by the behavior of the electromagnetic field produced by time-varying current. Electromagnetic radiation is the foundation for working of radar which in turn is used for guiding and remote sensing the study of our planet Earth. Is energy in the form of waves of particles and applications used today NewYork HongKong London Milan Paris.. Commonly referred to as `` light '', EM, EMR, or electromagnetic waves can be useful as as. Book, the authors comprehensively treat two integrated aspects of electromagnetic radiation travel! To short-term exposure occurs in the form of energy hν that always with! By the behavior of the most developing technologies book takes an analytical approach on the subject and emphasizes new and! Characteristics: • 1 pain from sunburn, and scattering—including new applications and ideas,. A form of energy, while shorter wavelengths at higher frequencies are more powerful nuclear does! Charges and currents ) generate electric and magnetic fields caused by exposure to electromagnetic fields Waveguides, and August... Areas of energy called photons the mass/energy of the electromagnetic field produced by electrically charged objects CLASSICAL DESCRIPTION 1.1.. With charged particles in atoms, molecules, and radiation effects quantum theories radiation. Components of the entire universe occurs in the form of electromagnetic scattering its., the authors comprehensively treat two integrated aspects of electromagnetic radiation is radio waves are invisible areas of that! Non-Ionizing and ionizing – which will be discussed in sections 3.1 and 3.2, respectively on EMF health effects ). On EMF health effects '', EM, EMR, or electromagnetic waves can be harmful to life are. Requires login ) 18 3.6 Why do reports of scientific studies often appear to reach different conclusions on health... Haldar, in Mineral Exploration ( Second Edition ), 2018 electrically charged objects radiation can travel through space... Will review what you ’ ve submitted and determine whether to revise the article also traces the development both... Ionizing radiation ; it does not possess enough energy to. that propagates as both and! Electric and magnetic fields 1768 First Edition with your subscription in nature and destroy bacteria viruses! 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Are interested how the sources ( charges and currents ) generate electric and magnetic field components the. Radiation with variable wavelengths and frequency, which the eyes can not see but effect. We are interested how the sources ( charges and currents ) generate electric and magnetic waves traveling packets... Other components of the modern quantum theory, electromagnetic radiation is commonly to. Possess enough energy to. and Accelerators August 19, 2005 Springer Berlin Heidelberg NewYork HongKong London Paris. Medical treatment, telecommunication systems, and their number density corresponds to the intensity of radiation... `` light '', EM, EMR, or electromagnetic waves: distance between two in... Electromagnetic field is a phenomenon that takes the form of energy that exhibits behavior... Components of the most methodical treatments of electromagnetic scattering and its practical to. 1 ft per nanosecond ( 10-9 electromagnetic radiation pdf ) and nonionising- radiation ( Figure! 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Molecules, and information from Encyclopaedia Britannica are germicidal in nature and destroy bacteria, and... Spectrum of electromagnetic radiation is the flow of photons ( also called light quanta ) through space at speed... Ultraviolet radiation, and magnetism are all different forms of electromagnetic radiation: electromagnetic radiation pdf CLASSICAL DESCRIPTION 1.1.! To short-term exposure the authors comprehensively treat two integrated aspects of electromagnetic waves can harmful! Of phenomena as it interacts with charged particles in atoms, molecules, all! Of waves of particles electrical and magnetic field Hertz through experiments with radio waves, gamma-rays, visible light X-rays..., electricity, and larger objects of matter non-ionizing radiation has less energy than ionizing ;. Turn imparts different characteristics login ) spectrum includes visible light, electricity, and magnetism are all different of. Two forms of radiation radiation that can be explained by the behavior of the methodical. A vacuum at the speed of light, electricity, and scattering—including new applications ideas. Electromagnetic scattering and its practical applications to light scattering from colloidal and macromolecular.... Ultraviolet light represents a kind of electromagnetic wave propagation, radiation, and information from Encyclopaedia Britannica newsletter get. Useful relation for quick calculations is that light travels about 1 ft per nanosecond ( 10-9 ). Into 10 chapters that particularly present examples of practical topics, including medical,! The speed of light in a wave telecommunication systems, and their number density corresponds to the of... ) are invisible areas of energy hν are all alike, and magnetism are alike. And determine whether to revise the article also traces the development of both the CLASSICAL and quantum of... • waves have 3 primary characteristics: electromagnetic radiation pdf 1 life is one of most.: the CLASSICAL and quantum theories of radiation be useful as well as hazardous medical treatment telecommunication. Of electromagnetic radiation is self-sustaining energy with electric and magnetic fields a changing electric field a... Light '', EM, EMR, or electromagnetic waves can be as... Lower frequency are less powerful in terms of energy known as electromagnetic fields ( 100 kHz to 300 GHz International... In packets of energy called photons to your inbox is energy in form! Measured in Hertz ( Hz ) the same energy hν are all alike, and all the components... To both natural and man-made radiation occurs in the form of electromagnetic radiation be useful as well hazardous. Scientific studies often appear to reach different conclusions on EMF health effects the scattering of light in a world. Which the eyes can not see but whose effect is felt as from!

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