Electromagnetic em waves carry energy through propagation in space. Electromagnetic waves other than light also have the. In these electromagnetic theory notes pdf, we will study the concepts learnt in the electricity and magnetism course to understand the properties of electromagnetic waves in vacuum and different media. This radiation propagates moves through space at 299,792 km per second about 186,000 miles per second. Can the students identify common uses of various wave types.
Higherfrequency em waves, with more electromagnetic vibrations per second, have. The emr spectrum is widely used in differ ent areas of science and technology. Radio waves have a wavelength greater than 30cm the length of a standard ruler. Along with the widespread use of technological products in daily life, the biological effects of electromagnetic waves started to. Concepts of electromagnetic fields wiley online library. Feb 07, 2017 the speed c of electromagnetic wave in vacuum is related to. Electromagnetic waves electromagnetic waves are those waves in which electric and magnetic field vectors changes sinusoidally and are perpendicular to each other as well as at right angles to the direction of propagation of wave. The electromagnetic spectrum is made up of six different types of waves. The frequency of an em wave also determines its characteristics and uses. Overview of department of defense use of the electromagnetic. The electromagnetic spectrum is the distribution of electromagnetic radiation according to frequency or wavelength. The electromagnetic spectrum goes from the waves with the lowest energy to those with the highest energy. Electromagnetic spectrum, the entire distribution of electromagnetic radiation.
Indeed light is just one form of electromagnetic radiation. Electromagnetic waves and their properties boundless physics. Pdf the electromagnetic spectrum and the associated types of light are especially useful in the field of medicine. This means that although they appear to be very different, in fact theyre all made of the same kind of vibrations but at different. All electromagnetic waves travel at the same speed 300,000,000 metres per second, which is the speed of light. Maxwells work thus unified the domain of electricity, magnetism and light. Notes for electronics engineering pdf ppt electronic communication and its terminology. Pdf electromagnetic em waves carry energy through propagation in space.
These short solved questions or quizzes are provided by gkseries. The electromagnetic spectrum is a series of frequencies ranging from radio waves to microwaves, visible light, x rays, and gamma rays. Electromagnetic radiation is radio waves, gammarays, visible light, and all the other components of the electromagnetic spectrum. Free download in pdf electromagnetic waves multiple choice questions and answers for competitive exams. Recognize that electromagnetic waves can travel through empty space without a medium. Faradays law describes how a timevarying magnetic field or flux induces an electric field. Benefits and hazards of electromagnetic waves, telecommunication. Israa alzoubi electromagnetic waves and their uses objective.
Notes for electronics engineering pdf ppt one thought on uses of electromagnetic waves. Visible light refers to electromagnetic waves ranging in wavelength from 400 nm to 700 nm. This book will provide a broad overview of em waves, both their theory and practical applications, with a special emphasis on lasers. Radio waves are used for wireless transmission of sound messages, or information, for communication, as well as for maritime and aircraft navigation. Making electromagnetic waves an em wave travels in all directions. Electromagnetic waves multiple choice questions and. Electromagnetic radiation wave nature properties and formula. Electromagnetic radiation shares many of the same traits as water waves. The use of electromagnetic radiation in the physiotherapy. Hsps45 communicate technical information about how some technological devices use the principles of wave behavior and wave interactions with matter to transmit and capture information. The motion of different waves enables scientists to classify them into.
The next four chapters discuss various aspects of optics, the science of light. Uses of electromagnetic waves communication systems oneway and twoway radar cooking with microwaves medical imaging x rays night vision infrared astronomy radio, wave, ir, visible, uv, gamma the electromagnetic spectrum relationship between frequency, speed and wavelength f l c f is frequency, l is wavelength, c is speed of. An echocardiogram uses sound waves to produce images of your heart. Chapter 2 the properties of electromagnetic radiation. These two parts of the spectrum share a lot of similarities and uses. Cbse 12th physics chapter notes on electromagnetic waves.
The department of defense dod uses electromagnetic radiation to enable military communications, navigation, radar, nonintrusive inspection of aircraft, and other equipment. Electromagnetic waves are transverse waves with a wide range of properties and uses. Very long distance communications with low power and simple antennas. 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.
Electromagnetic waves and lasers second edition book. This radiation associates with entangled electric and magnetic fields. With their low frequencies, radio waves have the least energy of electromagnetic waves, but they still are extremely useful. Here we first introduce electromagnetic waves and some of their properties including their structure, energy, and momentum. Electromagnetic waves are produced when an electric charge vibrates or accelerates and can travel through empty space or through matter. Electromagnetic radiation electromagnetic radiation radio waves. Electromagnetic radiation radiant energy that exhibits wavelengthlike behavior and travels through space at the speed of light in a vacuum. Transition between ground wave and mode predominance and sky wave ionospheric hops. They do not require any medium for their propagation. Its technological use by marconi and others led in due course to the. As a short treatise on this subject matter, this book aims to offer a quick overview that will allow the reader to gain a competent general understanding of electromagnetic waves and lasers, and how to use lasers in optical systems. Because gamma rays can kill living cells, they are used to kill cancer cells without having to resort to difficult surgery. Changes in the nuclei of atoms cause the emission of high frequency gamma rays. Shorter wavelength higher frequency waves are measured by their length wavelength in meters.
H magnetic vector b induction vector 0, 0 permeability and permittivity of vacuum r, r relative permeability and permittivity maxwells concept of electromagnetic waves is that a smooth wave motion exists in the magnetic and electric force fields. Laser or optical tweezers is an exciting new technique that allows manipulation of microscopic structures or of. However, radio waves, visible light, xrays, and all the other parts of the electromagnetic spectrum are fundamentally the same. Note that we didnt need to use the second of maxwells equations to derive this. Radio waves are the broad range of electromagnetic waves with the longest wavelengths and lowest frequencies. Electromagnetic radiation emr is radiated by atomic particles at the source the sun, propagates through the vacuum of space at the speed of light, interacts with the earths atmosphere, interacts with the earths surface, interacts with the earths atmosphere once again, and. Military use of the electromagnetic spectrum frequencies or observe heat signatures of personnel, missiles, aircraft, artillery, and vehicles. The differing behaviours of different groups in the electromagnetic spectrum make them suitable for a range of uses. Thus, common technologies use electromagnetic radiation to enable a wide variety of uses. Technological applications of electromagnetic waves video. However, we can still detect the electromagnetic waves. Physics notes for class 12 chapter 8 and 15 electromagnetic. Questions and answers about biological effects and. Making electromagnetic waves when an electric charge vibrates, the electric field around it changes creating a changing magnetic field.
The uses of electromagnetic waves, this section describes some of the qualities and uses of different waves on the electromagnetic spectrum. They are produced by oscillating or accelerating charged particles. For each of the waves you have identified give their wavelength and find one use for radiation in that range. Therefore, visible light, gamma rays, and microwaves are really the same thing.
They are used for many tasks, for example, remote controls for tvs and video recorders, and physiotherapists use heat lamps to help heal sports injuries. The equation of plane progressive electromagnetic wave can be written as e e o sin. Electromagnetic spectrum, the entire distribution of electromagnetic radiation according to frequency or wavelength. The radio in your car receives the radio waves, decodes the information, and uses a speaker to change it back into a sound wave, bringing sweet music to your. Ask the students to identify as many possible types of electromagnetic waves that they can. The variation of electric and magnetic fields, perpendicular to each other, producing electromagnetic disturbance in space at right angles to each other, which have properties of waves and propagate through free space without any materialistic medium is called electromagnetic wave. Radio waves are commonly used for audio communications i. Dod also heavily relies on electromagnetic radiation for intelligence, surveillance, and reconnaissance isr. Ultraviolet waves and their relationship to sunburn and skin cancer. Radio waves are often used to transmit data and have been used for all sorts of applications including radio, satellites, radar, and computer networks. Electromagnetic radiation transports energy from point to point. The principle behind this phenomenon is used in many electric. Introduction the electromagnetic spectrum is the collective name for all types of radiation.
It might seem hard to believe that the same form of energy browns your toast, brings you broadcast television, and makes the page you are now reading visible. Dods use of the spectrum as a critical enabler, and, as a result. These waves are used in the manufacture of radars which helps the forces discover the borders and know the entry of any enemies easily through radar imaging, pala in. Radio waves are located at one end of the electromagnetic spectrum. All substances give off electromagnetic radiation in the form of electromagnetic waves. A useful relation for quick calculations is that light travels about 1 ft per nanosecond 109 s. The motion of different waves enables scientists to classify them into different parts of the electromagnetic spectrum. The various types of em waves differ from each other in. Electromagnetic waves physics definition notes pdf download. In terms of a stream of massless particles, called photons, each travelling at the speed of light in a wave like pattern, electromagnetic radiation can be represented.
The frequency is the number of electromagnetic waves passing a given point in one second. Transverse wave a wave in which the particles of the medium oscillate in paths perpendicular to the direction of wave motion. The term radio waves refers to electromagnetic radiation with wavelengths greater than about 0. Hertz, in 1885, experimentally demonstrated the existence of electromagnetic waves. This chapter gives an introduction to electromagnetic waves in collision less. Radio waves, microwaves, infrared waves, visible light, ultraviolet light. Electromagnetic waves can also be described by their frequency that is, how many times a wave waves in a unit of time. 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. For instance, imagine yourself as a ticket taker at a. This commonly used test allows your doctor to see how your heart is bea ng and. The electromagnetic spectrum cie igcse physics revision.
Oct 09, 2010 resulting from the technological innovations, the use of electromagnetic fields gradually increases and thus people are exposed to electromagnetic waves at levels much higher than those present in the nature 1,2,5. With infrared waves, distances are short such as a few meters for television remote control while radio waves can reach as far as thousands or even millions of kilometers for deepspace radio communications. The information is propagated by electromagnetic radi. Describe how radio waves are used in cell phone wireless communication. Electromagnetic waves multiple choice questions and answers. Dec 10, 2019 xrays are electromagnetic waves that can be used in aptly named xray machines to see inside your body and diagnose various diseases.
State two differences between the electromagnetic radiation emitted from a laser and the. Different uses of electromagnetic waves type of electromagnetic wave size of wavelength uses radio waves ranging from about 0. Jul 29, 2015 radio waves radio waves have the longest wavelengths of all the electromagnetic waves. Aug 11, 2020 in spectroscopy, the frequency of the electromagnetic radiation being used is usually expressed in hertz hz, that is, cycles per second. Electromagnetic applications in biology and medicine. In any region in which there is a temporal change in. Other wavelengths of electromagnetic waves are invisible. Electromagnetic waves do not need a physical medium to propagate. Introduction to the electromagnetic spectrum science mission. Handwritten electromagnetic theory notes pdf lecture download.
A quantum is a small, definite quantity of electromagnetic radiation whose energy is directly proportional to its frequency. The information is imposed on the electromagnetic carrier wave as amplitude modulation am or as frequency modulation fm or in digital form pulse modulation. What type of electromagnetic radiation has the next lowest frequency. Behaviour and uses of electromagnetic waves properties. The radio in your car receives the radio waves, decodes the information, and uses a speaker to change. For example, a typical radio wave transmitted by an fm radio station has a wavelength of about three 3 meters and a frequency of about 100 million cycles waves per second or 100 mhz. 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. Behaviour and uses of electromagnetic waves properties, uses. Electromagnetic radiation electromagnetic waves perpendicular waves combing the electric and magnetic fields. This instructional segment uses these everyday applications to lead to a larger decision about where to buy tickets for an upcoming concert and designing a new entertainment venue. Some of the waves are also hazardous to human body tissues.
Its technological use by marconi and others led in due course to the revolution in communication that we are witnessing today. Waves electromagnetic spectrumlight in our homes the transfer of energy runs our garage door openers, tv, radios, etc. Electromagnetic radiation is the means for many of our interactions with the world. Pdf uses of electromagnetic radiation in medical science.
Electromagnetic waves properties, uses and hazards of. Because every object gives off ir waves, we can use them to see in the dark. It is used for night vision and security cameras as infrared radiation is visible in daytime or nighttime police use it to catch criminals, army use it to detect enemy dangers. The most common wireless technologies use electromagnetic wireless telecommunications, such as radio or infrared signals. These short objective type questions with answers are very important for board exams as well as competitive exams. Below are examples of electromagnetic radiation uses and applications. A radio detects a different portion of the spectrum, and an x ray machine uses yet another portion. Em spectrum have different uses is usually fairly easily. In applications across civil, commercial, and government sectors, the characteristics of the waves used often drive the use. Vhf 30 mhz to 100 mhz with low power and small antennas, primarily for local use. Information could be encoded in the frequency content, intensity, or polarization of the electromagnetic wave.
This means that electromagnetic waves can have hazardous effects on body cells. Radio waves are used for communication such as television and radio. In physiotherapy, these electromagnetic modalities are generally used to expedite recovery of soft tis. Electromagnetic wave em waves that need no medium to travel. Other applications militaries use the spectrum to target and potentially attack adversaries. Although not strict, the term magnetic field is often used for magnetic induction in. This video describes some of the qualities and uses of different waves on the electromagnetic spectrumfor more information on gcse physics visit. Many technologies already make good use of some part of the electromagnetic spectrum. Technological applications of electromagnetic waves. Making electromagnetic waves the magnetic and electric fields create each other again and again.
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