The electromagnetic spectrum is the range of frequencies the spectrum of electromagnetic radiation and their respective wavelengths and photon energies the electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 10 25 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an. Electromagnetic em radiation is created whenever charges accelerate. The visible spectrum, as seen in a rainbow, is only a small part of the whole electromagnetic spectrum. This means that although they appear to be very different, in fact theyre all made of the same kind of vibrations but at different. He did often recount how his experience with understanding radiation theory from his solution of. Other examples of em radiation are microwaves, infrared and ultraviolet radiation, xrays and gamma rays. The frequency of an em wave also determines its characteristics and uses. When people hear the word radiation, they often think of atomic energy, nuclear power and radioactivity, but radiation has many other forms. Electromagnetic radiation is a form of energy that is produced by oscillating.
The electromagnetic spectrum comprises the span of all electromagnetic radiation and consists of many subranges, commonly. In physiotherapy, these electromagnetic modalities are generally used to expedite recovery of soft tissue injuries or relieve the pain 5. Electromagnetic radiation, in classical physics, the flow of energy at the universal speed of light through free space or through a material medium in the form of the electric and magnetic fields that make up electromagnetic waves such as radio waves, visible light, and gamma rays. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, by a prism. Stephanboltzmann law says that if this body is a black body, one which perfectly absorbs and emits radiation, the radiation released is equal to the temperature raised to the fourth power. Different laws followed by electromagnetic radiation. Some other forms of electromagnetic radiation are xrays, microwaves, infrared. Pdf the electromagnetic spectrum and the associated types of light are especially useful in the field of medicine.
This include ordinary xray film, the use of contrast media, fluorescent screens, image intensifiers, ct and the use of digital technology to all xray systems. Let us use the above results to investigate the interaction of an atomic electron with classical i. Electromagnetic radiation an overview sciencedirect topics. The planes of the fields are at right angles to each other and to the direction in which the wave is travelling. Electromagnetic radiation properties and laws just btech. Ionizing radiation ionising radiation is radiation, traveling as a particle or electromagnetic wave, that carries sufficient energy to detach electrons from atoms or molecules, thereby ionizing an atom or a molecule. The main methods of therapy used for that purpose are. Higherfrequency em waves, with more electromagnetic vibrations per second, have. Electromagnetic energy is a term used to describe all the different kinds of energies released into space by stars such as the sun. Electromagnetic pulse emp september 2003 fact sheet 320090 division of environmental health office of radiation protection what is emp and how is it created. Examples of energy within the electromagnetic spectrum include xrays most widely clinically used to treat malignant lesions, visible light, infrared light, and.
The electromagnetic spectrum and the associated types of light are especially useful in the field of medicine. Atoms are a million times thinner than a single strand of human hair, and are composed of even smaller particles some of which are electrically charged. Electromagnetic radiation released is related to the temperature of the body. Electromagnetic ionizing radiation is used in pediatric healthcare for both imaging and cancer. Wave model of electromagnetic radiation in the 1860s, james clerk maxwell 18311879 conceptualized 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 s1 or 186,282. The waves propagate through a vacuum at the speed of light. Introduction to the electromagnetic spectrum science. Electromagnetic waves or em radiation has two constituents. Students would explain what an xray machine is used for, how it works scientifically, and how it uses electromagnetic waves. Em waves are energy transported through space in the form of periodic disturbances of. In everyday communication, the term electromagnetic radiation refers to technically produced electric. Electromagnetic radiation is characterized by a broad range of wavelengths and frequencies, each associated with a specific intensity or amplitude and quantity of energy.
Pdf uses of electromagnetic radiation in medical science. Xrays are a type of radiation called electromagnetic waves. This is because different tissues absorb different amounts of radiation. Electromagnetic induction waves interference of waves. It is quantized in that for a given frequency, its energy occurs as an integer times h, in which h is a fundamental constant of nature known as plancks constant. Technological applications of electromagnetic waves. The use of electromagnetic radiation in the physiotherapy. At close range, this energy disturbs the metabolism and electrical activities of living. The electromagnetic spectrum is the complete spectrum or continuum of all forms of light an electromagnetic wave consists of electric and magnetic fields which vibrate thus making waves.
Uv is highenergy electromagnetic radiation that is found between visible light and xrays in the electromagnetic spectrum. But the emerging problems of quantum electrodynamics caught his attention, and he never returned to classical electrodynamics while at harvard. Calcium in bones absorbs xrays the most, so bones look white. This energy for remote sensing instruments is in the form of electromagnetic radiation emr. Em radiations are microwaves, infrared and ultraviolet light, xrays and gammarays. Remote sensing is concerned with the measurement of emr returned. Microwaves are used for highbandwidth communications, radar and as a heat source for microwave ovens and industrial applications. They are categorized in spectrum charts by the artificial techniques we use to. Em radiation or electromagnetic radiation is an energy form that is present all around us and takes various forms like microwaves, radio waves, gamma rays, xrays, etc. The crt monitor uses fast beam of electrons that generates pulsed electromagnetic radiation carrying energy. This article provides an extensive summary of the types of electromagnetic radiation and their thermal and molecular effects on the human body figure 1 electromagnetic spectrum.
Pdf basics of electromagnetic radiation researchgate. Electromagnetic radiation is reflected or absorbed mainly by several gases in the earths atmosphere, among the most important being water vapor, carbon dioxide, and ozone. Starting from low frequency and working up, here are a few. Electromagnetic radiation, however, has particlelike properties in addition to those associated with wave motion.
Howmechanismworks what is electromagnetic radiation. Electromagnetic spectrum, the entire distribution of electromagnetic radiation according to frequency or wavelength. Visible light radiation that comes from a lamp in someones house or radio wave radiation that comes from a radio station are two types of electromagnetic radiation. The images show the parts of your body in different shades of black and white. The general nature of the effects is noted for different ranges. In this piece of article, we will discuss electromagnetic radiation and its properties. All electromagnetic waves travel at the same speed 300,000,000 metres per second, which is the speed of light. Everyday we are exposed to ultraviolet uv radiation emitted by the sun. You may work your way sequentially through this flipchart or use the. The electromagnetic em spectrum is a name that scientists give a cluster of radiation when they want to talk about them as a group.
The most important mechanism for electromagnetic pulse emp production from a nuclear detonation is the ionization of air molecules by gamma rays generated from the explosion. Although all electromagnetic waves travel at the speed of light in a vacuum, they do so at a wide range of frequencies, wavelengths, and photon energies. Later the concept was expanded greatly to include any interaction with radiative energy as a. The electromagnetic spectrum 2 cesars booklet the electromagnetic spectrum the colours of light you have surely seen a rainbow, and you are probably familiar with the explanation to this phenomenon. Radiation is energy in the form of waves or streams of particles. For microwaves, the charges oscillate in a resonance or tank circuit, consisting of a capacitor with capacitance c and a coil with selfinductance l. Some radiation, such as visible light, largely passes is transmitted through the atmosphere.
Xray imaging creates pictures of the inside of your body. Electromagnetic spectrum and its impact on human life. The electromagnetic spectrum is divided into five major types of radiation. Radiation is energy that travels and spreads out as it goes.
Radio waves are the lowestfrequency waves in the em. Sources radio wavesnmr electromagnetic waves are produced a. All life has evolved in an environment filled with radiation. Electromagnetic radiation is energy that spreads out as it travels. The electromagnetic spectrum t e harrington middle school. Wavelengths and uses the who, what, where, and when of wavelengths a forensic light source is made up of a powerful lamp containing the ultraviolet, visible and infrared components of light. Radio waves, infrared rays, visible light, ultraviolet rays, xrays, and gamma rays are all types of electromagnetic radiation. Electromagnetic radiation emr the first requirement for remote sensing is to have an energy source to illuminate the target. All electromagnetic waves travel at the same speed 300,000,000 metres per second. Introduction to radiation canadian nuclear safety commission. Electromagnetic radiation is a form of energy that propagates as both electrical and magnetic waves traveling in packets of energy called photons. This occurs, for example, when timevarying currents run up and down the transmitter of a radio station or when atoms bounce around inside a fluorescent light bulb. This interactive tutorial explores the relationship between frequency, wavelength, and energy, and enables the visitor. In such a wave, timevarying electric and magnetic fields are mutually linked with each other at right angles and.
Radio waves are used in remote sensing, where hydrogen gas in. Electromagnetic radiation principles and concepts as applied to. Humans cannot see uv radiation but research has shown that bees, birds, butterflies and other insects can. The forces at work in radiation are revealed upon examining the structure of atoms. Electromagnetic radiation emr and its application in. There is a spectrum of electromagnetic radiation with variable wavelengths and frequency, which in. We deal with both normal and nonnormal angles of incidence. Emf meters a practical guide to using an emf meter. It then filters down the light into individual color bands wavelengths that enhance the. Based on frequency and wavelength electromagnetic energy is divided into several categories i. This is mainly due to pulsed electromagnetic radiation and artificial light from the monitor. Describe how a microwave oven uses microwaves to quickly heat food. The same thing happens if you watch tv for long time. There are many uses for radio waves, and so the category is divided into many subcategories, including microwaves and those electromagnetic waves used for.
Electromagnetic radiation is commonly referred to as light, em, emr, or electromagnetic waves. Wavelength and electromagnetic radiation can be related using the following law. When electromagnetic radiation is spread out according to its wavelength, the result is a spectrum, as seen in fig. Basic electromagnetic wave properties java tutorial. 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. Application of radiation in medicine chapter 9 radiation used for diagnostic purposes in this chapter we shall discuss the use of radiation of different kind for medical imaging.
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