Lecture 22 electromagnetic waves in a dielectric, dispersion relation. 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. Sources and effects of electromagnetic fields coordinate systems vector fields gradient, divergence, curl theorems and applications electrostatic fields coulombs law electric field intensityefi due to line, surface and volume charges work done in moving a point charge in electrostatic. The vector r denotes the location in space where the.
Newly updated as a digital pdf for home or distance learning. Apply maxwells equations k r e e0 exp j t k x b b0 exp j t k x r r rr r r rr. Electromagnetic radiation covers a wide range of wavelength, from 1010 m for cosmic rays to 1010 m for electrical power waves. Most of the lectures and course material within open yale courses are licensed under a creative commons attributionnoncommercialshare alike 3. Editor, the feynman lectures on physics new millennium edition. We have qualitatively demonstrated that there are maxima and minima in the radiation field from two sources, and our problem now is to describe the field in mathematical detail, not just qualitatively. Commonly observed propagation effects are depicted. Resonance, destructive resonance, electromagnetic waves, speed of light, radio tv, distance determinations using radar and lasers author. Radio waves, tv waves, x rays and ultrasound waves used in medical diagnosis and treatment electromagnetic waves. Electromagnetic standing waves in this lecture, we shall see how the waves may be \captured as standing waves in a region of free space bounded by conducting materials an electromagnetic cavity. Electromagnetic waves 1 light as waves in previous classes 15a, high school physics, you learned to think about light as rays. The electromagnetic force is carried by electromagnetic fields composed of electric fields and magnetic fields, and it is responsible for electromagnetic radiation such as light. Sound waves, water waves, seismic waves mechanical waves.
The next four chapters discuss various aspects of optics, the science of light. Electromagnetic waves can be generated by oscillating electric charges. Rf and microwave courses university lectures and publications. Plane electromagnetic waves can be expressed as e c. Applications of electromagnetic fields and waves, maxwells equations, electrostatics, electric scalar potential, poisson equation, laplace equation, faradays law and electromagnetic induction, electromagnetic wave equation, hertzian dipoles, antenna arrays and electromagnetic scattering. Unless explicitly set forth in the applicable credits section of a lecture, thirdparty content is not covered under the creative commons license.
The current book is an outgrowth of the lecture notes that i prepared for the fourcredit course electrodynamics that was introduced in the uppsala university curriculum in 1992, to become the. Bharadwaj,department of physics and meteorology, iit kharagpur. My hand written class lecture notes are being scanned and uploaded for you to view. Maxwells equations have wavelike solutions for the electric and magnetic elds in free space. An introduction to the theory of electromagnetic waves. This section contains lecture notes in both pdf and powerpoint formats. Here you can download the free lecture notes of electromagnetic theory pdf notes emt pdf notes materials with multiple file links to download. In our daily lives we face many examples of waves and oscillations. In this openended and engaging ngss high school research project, students are challenged to investigate the behavior and interactions of one of the electromagnetic waves to fulfill the ngss performance expectation hsps45. Substitute amperes law for a charge and currentfree region.
From source to detector sound from an instrument to ear cell phone to cell tower and vice versa em waves water waves a disturbance in the water moves outward. Find materials for this course in the pages linked along the left. Some of the slides include animations, which can be seen by viewing the powerpoint file as a slide show. When you come back from the break we will start doing optics. Electromagnetic standing waves in the previous lecture, we saw that. Because the electric charge is in motion, it also has a magnetic field around it. It will also be helpful for students in preparing them for their engineering syllabus. Nature of electromagnetic waves a general plane wave with angular frequency. For any instant and position, apply the relationship between the electric field magnitude e, the.
Electromagnetic waves such as light, tv, radio, etc. This is the threedimensional wave equation in vector form. In order to read the online edition of the feynman lectures on physics, javascript must be supported by your browser and enabled. Imrana ashraf zahid quaidiazam university, islamabad pakistan. In both classical electromagnetic theory and in quantum electrodynamics, the electromagnetic field or photon field is a vector field represented by a 4vector potential. This relation implies that electromagnetic waves are dispersionless with velocity c. This training material will be useful for electrical engineering students as well as those who are preparing gate exams. Expressions for the energy density and energy ow in an electromagnetic eld may be obtained from poyntings. The fields e and b and are perpendicular to the direction of propagation v em. Traveling waves waves propagate from one place to another. The list of the various types of electromagnetic waves, ranging from radio transmission waves to nuclear gammaray. Please be warned that these are the notes i prepare for myself to lecture from they are not in general carefully prepared for others to read.
In previous classes 15a, high school physics, you learned to think about light as rays. All electromagnetic waves travel in a vacuum with the same speed, a. Em waves, wave propagation in linearhomogeneousisotropic media part. This raytracing business is known as geometrical optics. One set of notes was a resonance equation, demonstrating that as the rate. Electromagnetic waves with wavelengths in the visible spectrum 10. For this we have included pdf notes of each chapter still updating. Lecture 12 electromagnetic waves in a vacuum, energy and momentum of em waves.
Lewin, center for future civic media, massachusetts institute of technology, mit. The lectures are uploaded as pdf files, so you will need adobe acrobat reader in order to read them. Of these sources, electromagnetic waves is by far the most important. Lee shows the electromagnetic wave equation can be derived by using maxwells.
Wave equations uniform plane wave motion in free space, conductors and dielectrics velocity, wave length, intrinsic impedence and skin depth poynting theorem poynting vector and its significance. In this chapter we shall discuss the subject of the preceding chapter more mathematically. E and b are perpendicular to each other in a manner such that e. Elec3115 electromagnetic engineering course outline. The fact that, unlike newtons laws, maxwells equations are already consistent with relativity is discussed. Longer wavelengths than red go into infrared, then microwaves, then radio waves. An incident pulse reflecting from a fixed point will be inverted. I hope, nevertheless that you will find them useful. Hopefully helpful comments on taking uiuc physics 436.
Pdf the electromagnetic spectrum is the complete spectrum or continuum. Lecture 11 chapter 16 waves i forced oscillator from last time slinky example coiled wire rope transverse waves demonstrator longitudinal waves magnetic balls. Maxwells equations in their final form are written down and then considered in free space, away from charges and currents. These are compiled by david tong, department of applied mathematics and theoretical physics, university of cambridge. 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. Feb 19, 2015 electromagnetic spectrum explained gamma x rays microwaves infrared radio waves uv visble light duration. Electromagnetic spectrum explained gamma x rays microwaves infrared radio waves uv visble light duration. But well now switch gears and talk about electromagnetic waves. Vibrations and waves are among the most important types of motion found in nature. Maxwells equations contain the wave equation for electromagnetic waves. Electromagnetic fields and waves lectures download book.
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. The wavelength and frequency of electromagnetic waves vary from very long wavelengths to extremely short. Okay, this is the final lecture on electromagnetism. 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. Electromagnetic waves are produced when something vibrates an electric charge that moves back and forth. Unsw australia school of electrical engineering and telecommunications elec3115 electromagnetic engineering course outline session 1, 2014 abstractthis is a summary of how elec3115 is organised and what students are expected to do and learn. 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. Laser or optical tweezers is an exciting new technique that allows manipulation of microscopic structures or of.
If you have have visited this website previously its possible you may have a mixture of incompatible files. The lectures are uploaded as pdf files, so you will need adobe acrobat. These lecture notes provide a comprehensive introduction to electromagnetism, aimed at undergraduates. Waves involving springsmasses, strings, and air molecules are things we can apply our intuition to. The physical meaning of the components of the wave equation and their applications are discussed.
Remember tracing light as lines through a curved lens and seeing whether the image was inverted or right side up and so on. Pdf files general orientational information, a brief history of electromagnetism. Hewson an introduction to the theory of electromagnetic waves longman group ltd. Links to rf and microwave courses university lectures and publications. Smaller wavelengths than blue are ultraviolet, then x rays than. This section serves as motivation for the fact that light is an electromagnetic wave. We use them to communicate, cook, and for medical purposes. These notes are aligned with our channels video lectures.
Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles. Some of the lecture notes were prepared in latex by alan dunn, a former mit student. Phys 201 lecture 15 maxwells equations and electromagnetic waves ii. Maxwells equations and electromagnetic waves ii overview. These files show spectra taken of the same star at 10 different moments. Chapter maxwells equations and electromagnetic waves. Introduction and electrostatics, magnetostatics, electrodynamics, electromagnetism and relativity, electromagnetic radiation, electromagnetism in matter.
Resonance, destructive resonance, electromagnetic waves, speed of light, radio tv, distance determinations using radar and lasers. Kindly note that some of these notes are not written by us and they are borrowed from student community. Electromagnetics theory vector analysis 9 lectures 00. Propagation of electromagnetic waves radiating systems must operate in a complex changing environment that interacts with propagating electromagnetic waves. The electromagnetism lecture notes is a book to provide an introduction to electromagnetism for electrical and electronics engineers. The beauty of a coral reef, the warm radiance of sunshine, the sting of sunburn, the xray revealing a broken bone, even microwave popcornall are brought to us by electromagnetic waves. Fall semester, 2011 all lecture notes, handouts, etc. Kondragunta jagadish babu,assistant professor chadalawada ramanamma engineering college autonomous chadalawada nagar, renigunta road, tirupati 517 506 department of electrical and electronics engineering. When an electric charge vibrates, the electric field around it changes. Maxwells equations and electromagnetic waves i overview. By applying the boundary conditions on the elds which we derive in the rst part of this lecture, we shall see how the electromagnetic eld. Electromagnetic waves are created by oscillating electric and magnetic fields. Pdf electromagnetism lecture notes university of cambridge.
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