11 電磁 IV

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11 電電 IV How did the electric guitar revolutionize rock? From acoustic to electric guitars

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11 電磁 IV. How did the electric guitar revolutionize rock? From acoustic to electric guitars. Sections. 電磁感應 物質的磁性 麥斯威爾方程式 電磁波 Lasers and X-rays. 11-1.1 Two symmetric Situations. current loop + magnetic field → torque torque + magnetic field → current. - PowerPoint PPT Presentation

Transcript of 11 電磁 IV

  • 11 IV How did the electric guitar revolutionize rock?From acoustic to electric guitars

  • SectionsLasers and X-rays

  • 11-1.1 Two symmetric Situationscurrent loop + magnetic field torquetorque + magnetic field current

  • 11-1.2 Two ExperimentsFirst Experiment A Magnet is moving with respect to the loop.

  • Second Experiment

    The switch S is closed or opend.

  • 11-1.3 Faradays Law of InductionAn emf is induced when the number of magnetic field lines that pass through the loop is changing. A Quantitative Treatment The magnetic flux

  • Faradays law

  • 1 A solenoid contains a coili =1.5 A n = 2.2104 turns / mA = 3.46 10-4m2 N = 130 turns25ms0

  • i =1.5 A n = 2.2104 turns / mA = 3.46 10-4m2 N = 130 turns25ms0

  • 11-1.4 Lenzs LawOpposition to pole MovementOpposition to flux changeElectric Guitars

  • 2 B = 4.0 t2 +2.0 t + 3.0 Ebat = 2.0V r = 0.20m

    EMBED Equation.2

    _988006547.unknown

    _1244752913.unknown

  • 3 B = 4 t2 x2W = 3.0m H = 2.0m t = 0.1s

    EMBED Equation.2

    _1244724452.unknown

    _1244752930.unknown

  • 11-1.5 Induction and Energy Transfers The work done by the applied force and the thermal energy produced in the wire.

  • The Power

  • Eddy currents induction stoves and EM braking

  • Eddy currents transformers

  • Eddy currents EM braking

  • Eddy currents metal detectors

  • The microphone

  • The tape recorder

  • Speaker

  • Voice-coil positioner of a HDD

  • 11-2.1 Magnetism of MatterHow can a clay-walled kiln reveal Earths magnetic field of the past?

  • The earths dipole field The mid-atlantic ridge 11-2.2 The Magnetic field of the Earth

  • 11-2.3 Magnetic MaterialsDiamagnetism ()Paramagnetism ()Ferromagnetism ()

    32-6 Diamagnetism

  • 11-2.4 Diamagnetism

  • 11-2.5 Paramagnetism

  • 11-2.6 Ferromagnetism(magnetic domain)

  • Hysteresis ()

  • 11-3.1 Maxwells Equations

  • 11-3.2 () ()

  • 11-3.3 Magnets and magnetic flux () Magnetic dipole: north/south pole

  • 11-3.4 Gauss Law for Magnetic Fields The net magnetic flux thru any closed Gaussian surface is zero.

  • 11-3.5 Gauss Law for electric Fields Flux enclosed charge

  • 11-3.6 Induced Magnetic Fields 3 ways to produce a magnetic field: by an electric current, by a magnetic material, and by induction.

  • 11-3.7 Induced Magnetic Fields

  • 11-3.8 Displacement Current

  • 11-3.9 Maxwells Equations

  • 11-4.1 Electromagnetic WavesThe Oscillating E and B FieldsA Most Curious Wave The ether ()

  • Light Electromagnetic WavesHertz () Radio WavesThe Electromagnetic SpectrumThe Relative Sensitivity of Human eyes 430nm 690nm11-4.2 Characteristics

  • 11-4.3 Maxwells Rainbow

  • 11-4.4 CometsWhat shapes the curved dust tail of a comet?

  • 11-4.5 Polarization ()Polarized LightThe Plane of PolarizationLinear, Circular and Elliptical polarization

  • Polarization of Light

  • 11-4.6 Liquid Crystal - I

  • Liquid Crystal - II

  • Liquid Crystal - III

  • LCD Liquid Crystal Display

  • 11-4.7 Reflection and Refraction ()

  • The Index of Refraction

    The Stealth Aircraft F-117A

  • 11-4.8 Chromatic Dispersion prisms and gratings

  • Rainbows

  • 11-4.9 Diffraction ()

    Why do the colors in a pointillism painting change with viewing distance?

  • The Fresnel Bright Spot (1819) Newton Poisson Fresnel

  • Double-slit diffraction (with interference)Single-slit diffraction

  • X-ray Diffraction

  • Braggs Law

  • 11-5.1 Theory of Lasers

  • He-Ne Lasers

  • Applications of Lasers

  • Compact Disc

  • 11-5.2 Theory of X-ray

  • X

  • Medical X-rays

  • 2D and 3D X-ray Images

  • !

    (0.3m)(1mm)Metastable states: 10-3 s vs 10-8 sHe: 20.61eV neon:20.66 eV / 18.70 eVBarcode scanning, CO2 laser welding and retina surgery