Learn section 1 electromagnetic waves with free interactive flashcards. This means that although they appear to be very different, in fact theyre all made of the same kind of vibrations but at different. Can you brain storm a list of radio waves used around you am and fm radio broadcasts cordless phones garage door opener wireless networks radio controlled toys. Electromagnetic waves and the electromagnetic spectrum video. Electromagnetics and applications mit opencourseware. The electromagnetic spectrum t e harrington middle school. Classical electromagnetic waves in free space before we can quantize the electromagnetic eld, we must develop some understanding of the classical electromagnetic eld. The covered topics include the fundamental physics of electromagnetic waves, theory of electromagnetic wave propagation and scattering, methods of computational analysis, material characterization, electromagnetic properties of plasma, analysis and applications of periodic. Simple derivation of electromagnetic waves from maxwells. Here we first introduce electromagnetic waves and some of their properties including their structure, energy, and momentum. In materials, like a prism, light can have dispersion. Electromagnetic field theory a problemsolving approach mit.
Special thanks are owed to the many mit faculty who have taught this subject and its three. The lake is the vacuum, the waves are light electromagnetic waves and the buoys are electrons. Laser or optical tweezers is an exciting new technique that allows manipulation of microscopic structures or of. Plane electromagnetic wave suppose the electric field of a plane electromagnetic wave is given by e,zte0 coskzt. Introduction classical electromagnetic waves in free space. This relation implies that electromagnetic waves are dispersionless with velocity c. From maxwells equation to the wave equation consider a region of empty space in which there is no charge density and no current density, i.
This book is dedicated to various aspects of electromagnetic wave theory and its applications in science and technology. And today we are going to look at a harder situation. Creation and reflection of electromagnetic plane waves creation. Maxwell equation e creates b and b creates e, therefore they can. This follows from the relativity fact that energy is equivalent. It is very important that the associated magnetic field also satisfies the wave equation. Massachusetts institute of technology department of physics 8. Maxwell calculated that electromagnetic waves would propagate at a speed given by the equation c 1 24. Electromagnetic waves unlike the waves we met last semester, such as sound waves or waves on a string, no medium is required it is not atoms moving around, but instead the electric and magnetic. 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. Just two years earlier he had joined the faculty at purdue, after a postdoc with oppenheimer in berkeley, and graduate study at columbia. Electromagnetic waves in a vacuum mit opencourseware. Electromagnetic vibrations, waves, and radiation the mit press. The next four chapters discuss various aspects of optics, the science of light.
In just afew simple equations he was able to show that the apparently distinct phenomena of. Electromagnetic waves would be capable of exerting forces on charges great distances from their source, and they might thus be detectable. If the motion of a magnetic field changes or accelerates, the magnetic field can provide an electric field 2008. Dudley, editor of the ieee press series on em waves on the significance of the books contribution to the field of electromagnetics. Electromagnetic radiation basics mit haystack observatory. Cell phones, electromagnetic radiation, and cancer. The main emphasis, however, is on the oscillatory aspects of the electromagnetic fieldthat is, on the vibrations, waves, radiation, and the interaction of electromagnetic. If f 2 the two waves add constructive interference note that if the transmitter and receiver are at approximately the same heights, close to the ground, and the antennas are pointed at each other, then d h t,h r and g t q a. We consider the electric field of a monochromatic electromagnetic wave with. Dec 10, 2014 electromagnetic waves plane wave solutions to maxwells equations polarization malus law this lecture is part of 8. Tata mcgrawhill education, oct 1, 2005 electromagnetic waves 580 pages.
Substitute amperes law for a charge and currentfree region. Some of the slides include animations, which can be seen by viewing the powerpoint file as a slide show. The wavelength and frequency of electromagnetic waves vary from very long wavelengths to extremely short. Em waves carry energy, momentum and angular momentum away from their source particle and can impart those quantities to matter with which they interact. Electromagnetic waves are created by oscillating electric and magnetic fields. Download our electromagnetic waves pdf by sadiku ebooks for free and learn more about electromagnetic waves pdf by sadiku march 26, 2014 chapter 31 6 the electromagnetic spectrum.
Lecture notes for an lowerdivision electromagnetism and optics course. This raytracing business is known as geometrical optics. Find materials for this course in the pages linked along the left. The visible electromagnetic spectrum goal the goal is to introduce the visible electromagnetic spectrum to students through use of materials readily available to most high school science classes. Electromagnetic waves maxwell, a young admirer of faraday, believed that the closeness of these two numbers, speed of light and the inverse square root of. Parabolic antenna for communicating with spacecraft.
The fields e and b and are perpendicular to the direction of propagation v em. Maxwells equation, electromagnetic waves mit opencourseware. Electromagnetic waves,attenuation constant,phase constant,propogation constant,intrinsic impedence,em wave in any general medium,em wave in free space, em wave in perfect dielectric,velocity,em waves in lossy dielectrics,em waves in good conductor,skin depth or depth of penetration,effect,poynting vector and poynting therom, waves are means of. Radio wavesradio waves viewed on earth from space have a much larger window on the electromagnetic spectrumalthough you cant see radio waves, you see them in use everyday. Electromagnetic plane waves propagate in empty space at the speed of light, c 1 o o. Maxwells equations contain the wave equation for electromagnetic waves.
To see how a changing electric field gives rise to a magnetic field, let us consider the process of charging of a capacitor and apply amperes circuital law given by chapter 4 b. In 1865, he predicted the existence of electromagnetic waves. The electromagnetic spectrum introductionvisible light 1 instructors guide to lab no. 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 ears. Electromagnetic radiation university of oklahoma physics. E and b are perpendicular to each other in a manner such that e. Electromagnetic radiation is energy radiated in the form of a wave as a result of the motion of electric charges 2008. And the speed at which these waves travel is the speed of light, c, and by c i mean three times 10 to the eight meters per second, because light is just and electromagnetic wave, light is a special example, one particular example of electromagnetic waves, but it is only. This section contains lecture notes in both pdf and powerpoint formats.
Electromagnetic waves course home syllabus instructor insights students common misconceptions. The book describes the features that vibrations and waves of all sorts have in common and includes examples of mechanical, acoustical, and optical manifestations of these phenomena that unite various parts of physics. Vibrations and waves, as taught in fall 2004 by dr. Vibrations and waves, fall 2016 view the complete course. Remember tracing light as lines through a curved lens and seeing whether the image was inverted or right side up and so on. Electromagnetic waves,attenuation constant,phase constant,propogation constant,intrinsic impedence,em wave in any general medium,em wave in free space, em wave in perfect dielectric,velocity,em waves in lossy dielectrics,em waves in good conductor,skin depth or depth of penetration,effect,poynting vector and poynting therom,waves are means of. Electromagnetic waves also makes connections between electromagnetics and simple equivalent circuit models wherever possible. Chapter maxwells equations and electromagnetic waves. We use them to communicate, cook, and for medical purposes. Electromagnetic waves are emitted by electrically charged particles undergoing acceleration, and these waves can subsequently interact with other charged particles, exerting force on them.
We deal with both normal and nonnormal angles of incidence. And the speed at which these waves travel is the speed of light, c, and by c i mean three times 10 to the eight meters per second, because light is just and electromagnetic wave, light is a special example, one particular example of electromagnetic waves, but it is only one example, these waves can have any wavelength. Electromagnetic waves can be used in a variety of ways. Electromagnetic vibrations, waves, and radiation george. The main emphasis, however, is on the oscillatory aspects of the electromagnetic fieldthat is, on the vibrations, waves, radiation, and the interaction of electromagnetic waves with matter. All electromagnetic waves travel at the same speed 300,000,000 metres per second, which is the speed of light. Lee shows the electromagnetic wave equation can be derived by using maxwells equation.
Electromagnetic waves 1 light as waves in previous classes 15a, high school physics, you learned to think about light as rays. At oscillations waves in the electromagnetic field. This will result in a linearly polarized plane wave travelling. Because of the significance of maxwells correction, the. Chapter maxwells equations and electromagnetic waves mit. Electromagnetic waves plane wave solutions to maxwells equations polarization malus law this lecture is part of 8. Massachusetts institute of technology research laboratory of electronics technical report no. Lee shows the electromagnetic wave equation can be. Choose from 500 different sets of section 1 electromagnetic waves flashcards on quizlet. The book exposes its readers to a considerable array of mathematical tools as well, ranging from orthogonal function expansions to perturbation techniques and duality, but physical intuition and approximate problem. This is the threedimensional wave equation in vector form.
We will return to this subject in more mathematical detail in a bit, but first the intuitive approach. Lecture notes 6 electromagnetic waves in matter electromagnetic wave propagation in linear media we now consider em wave propagation inside linear matter, but only in regions where there are no free charges free 0 andor free currents kfree 0 i. Simple derivation of electromagnetic waves from maxwells equations by lynda williams, santa rosa junior college physics department assume that the electric and magnetic fields are constrained to the y and z directions, respectfully, and that they are both functions of only x and t. That is why we call these waves transverse electromagnetic tem waves. This text was developed over a fiveyear period during which its authors were teaching the subject. Electromagnetic theory pdf notes emt pdf notes smartzworld.