210 likes | 378 Views
Electricity and Magnetism INEL 4151. Sandra Cruz-Pol, Ph. D. ECE UPRM Mayagüez, PR. Electricity => Magnetism. In 1820, Prof. Oersted discovered that a steady current produces a magnetic field while teaching a physics class. . http://micro.magnet.fsu.edu/electromag/java/faraday/index.html.
E N D
Electricity and MagnetismINEL 4151 Sandra Cruz-Pol, Ph. D. ECE UPRM Mayagüez, PR
Electricity => Magnetism • In 1820, Prof. Oersted discovered that a steady current produces a magnetic field while teaching a physics class. http://micro.magnet.fsu.edu/electromag/java/faraday/index.html
Would magnetism would produce electricity? Eleven years later, and at the same time, • Mike Faraday in London and • Joe Henry in New York discovered that a time-varying magnetic field produces an electric current!
Electromagnetics was born! • This is the principle of motors, hydro-electric generators and transformers operation. This is what Oersted discovered accidentally: *Mention some examples of em waves
Some terms • E = electric field intensity [V/m] • D = electric field density • H = magnetic field intensity, [A/m] • B = magnetic field density, [Teslas]
Moving loop in static B field When a conducting loop is moving inside a magnet (static B field), there’s a force on the charges. http://www.walter-fendt.de/ph14e/electricmotor.htm http://micro.magnet.fsu.edu/electromag/java/generator/dc.html Encarta®
Who was NikolaTesla? • Find out what inventions he made • His relation to Thomas Edison • Why is he not well know?
Vector Analysis Review: • What is a vector? • How to add them, multiply, etc,? • Coordinate systems • Cartesian, cylindrical, spherical • Vector Calculus review
Vector • A vector has magnitude and direction. • In Cartesian coordinates (x,y,z):
Example Given vectors A=ax+3az and B=5ax+2ay-6az • (a) |A+B| • (b) 5A-B • (c) the component of A along y • (d) a unit vector parallel to 3A+B Answers:(a)7(b)(0,-2,21)(c)0(d) ± (0.9117,.2279,0.3419)
Vector Multiplications Note that: • Dot product • Cross product
Also… • Multiplying 3 vectors: • Projection of vector A along B: Scalar: Vector:
Coordinates Systems • Cartesian (x,y,z) • Cylindrical (r,f,z) • Spherical (r,q,f)
Theorems • Divergence • Stokes’ • Laplacian Scalar: Vector: