Electricity and Magnetism INEL 4151

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Electricity and MagnetismINEL 4151

• Sandra Cruz-Pol, Ph. D.
• ECE UPRM
• Mayagüez, PR

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Electricity gt 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/farada
y/index.html
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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!

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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
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http//ece.uprm.edu/pol/cursos
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Some terms

• E electric field intensity V/m
• D electric field density
• H magnetic field intensity, A/m
• B magnetic field density, Teslas

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Maxwell Equations in General Form
Differential form Integral Form
Gausss Law for E field.
Gausss Law for H field. Nonexistence of monopole
Faradays Law
Amperes Circuit Law
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Moving loop in static B field

• When a conducting loop is moving inside a magnet
  (static B field), theres a force on the charges.
  
• http//www.walter-fendt.de/ph14e/electricmotor.htm
  
• http//micro.magnet.fsu.edu/electromag/java/genera
  tor/dc.html

Encarta
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Who was NikolaTesla?

• Find out what inventions he made
• His relation to Thomas Edison
• Why is he not well know?

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Vector Analysis Review

• What is a vector?
• How to add them, multiply, etc,?
• Coordinate systems
• Cartesian, cylindrical, spherical
• Vector Calculus review

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Vector

• A vector has magnitude and direction.
• In Cartesian coordinates (x,y,z)

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Vector operations
Commutative
Associative
Distributive
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Example

• Given vectors Aax3az and B5ax2ay-6az
• (a) AB
• (b) 5A-B
• (c) the component of A along y
• (d) a unit vector parallel to 3AB

Answers (a) 7 (b) (0,-2,21) (c) 0 (d)
(0.9117,.2279,0.3419)
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Vector Multiplications

• Dot product
• Cross product

Note that
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Also

• Multiplying 3 vectors
• Projection of vector A along B

Scalar Vector
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Coordinates Systems

• Cartesian (x,y,z)
• Cylindrical (r,f,z)
• Spherical (r,q,f)

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Cylindrical coordinates
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Spherical coordinates
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Vector calculus review
Del (gradient)
Divergence
Curl
Laplacian (del2 )
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Theorems

• Divergence
• Stokes
• Laplacian

Scalar Vector