Dr. C.K.Narayanappa Department of Medical ElectronicsM S Ramaiah Institute of Technology, Bengaluru-560054

I hear and I forget. I see and I believe. I do and I understand. - Confucius

Education is the manifestation of perfection already in man (Swami Vivekananda)

Students are not of our generation, where they sit down and listen. I think things have changed now; they want to explore, cut and paste.

Teaching must include two major components: sending and receiving informationEvaluate traditional teaching methods as well as multimedia teaching methodsAny communication methods that serve this purpose without destroying the objective could be considered as innovative methods of teaching.Benefits of innovative methodsImprove Learning process Strengthen governance

Pre-technology education context, the teacher is the sender or the source.

The educational material is the information or message.

The student is the receiver of the information.

The delivery medium: chalk-and- talk method overhead projector (OHP) transparencies.

In such a lecture students assume a purely passive role and their concentration fades off after 15-20 minutes.

Teaching in classroom using chalk and talk is one way flow of informationTeachers often continuously talk for an hour without knowing students response and feedback.The material presented is only based on lecturer notes and textbooks.There is insufficient interaction with students in classroom.More emphasis has been given on theory without any practical and real life time situations.Learning from memorization but not understanding.

TextImagesAudioVideoAnimation

TRADITIONAL METHOD A ONE WAY FLOW

MULTIMEDIA LEARNING AN INTERACTIVE LEARNING PROCESS

Innovative way Mind Map. Making notes with keywords and images.visual and sensory tools at our disposal.Recollect information for long time.

Electrostatics Magnetostatics Time varying fieldsWaves*

Knowledge of vector algebra and vector calculuscompact mathematical representations of complicated phenomenaAllow for easy visualization and manipulation

Reread the concepts carefully until you can do the derivations and solve the problems without confusionMake sure that you know the basic formulae by heartMake sure that you know units of all quantities of EMFTVisualize the problems with sketchesTell your mind that just you are learning only four Maxwells equations and their applications

A scalar field is a function that gives us a single value of some variable for every point in space.Examples: voltage, current, energy, temperatureA vector is a quantity which has both a magnitude and a direction in space.Examples: velocity, momentum, acceleration and force

VECTOR REPRESENTATION3 PRIMARY COORDINATE SYSTEMS: RECTANGULAR CYLINDRICAL SPHERICALExamples:Sheets - RECTANGULARWires/Cables - CYLINDRICALSpheres - SPHERICAL

Orthogonal Coordinate Systems: (coordinates mutually perpendicular)Spherical CoordinatesCylindrical CoordinatesP (x,y,z)P (r, , )P (, , z)xyzP(x,y,z)zxyzP (, , z)rzyxP(r, , )Rectangular Coordinates

Cartesian CoordinatesP(x,y,z)Spherical CoordinatesP(r, , )Cylindrical CoordinatesP(r, , z)xyzP(x,y,z)zrxyzP (, , z)rzyxP(r, , )P (, , z)

Cartesian and cylindrical(x, y, z) to (,,z)

(,,z) to (x, y, z)

Cartesian and CylindricalVectoral Transformation

Cartesian and Spherical(x, y, z) to (r,,)

(r,,) to (x, y, z)

Cartesian and Spherical Vectoral Transformation

Cartesian CoordinatesPage 109

Cylindrical Coordinates:Distance = dfDifferential Distances: ( d, df, dz )

Cylindrical Coordinates:Differential Distances: ( d, rdf, dz )Differential Surfaces:Differential Volume:

Spherical Coordinates:Distance = r sinq dfDifferential Distances: ( dr, rdq, r sinq df )

Spherical CoordinatesDifferential quantities:

Length:

Area:

Volume:Pages 113-115Back

Representation of differential length dl in coordinate systems:rectangularcylindricalsphericalMETRIC COEFFICIENTS

Representation of differential surface element:Vector is NORMAL to surfaceSURFACE NORMAL

Relate Electric and Magnetic fields generated by charge and current distributions.E = electric fieldD = electric displacementH = magnetic field intensityB = magnetic flux density= charge densityj = current density0 (permeability of free space) = 4 10-7 0 (permittivity of free space) = 8.854 10-12 c (speed of light) = 2.99792458 108 m/s

*Equivalent to Gauss Flux Theorem:

Gauss law for magnetism:

The net magnetic flux out of any closed surface is zero. Surround a magnetic dipole with a closed surface. The magnetic flux directed inward towards the south pole will equal the flux outward from the north pole. If there were a magnetic monopole source, this would give a non-zero integral. Gauss law for magnetism is then a statement thatThere are no magnetic monopoles

Equivalent to Faradays Law of Induction:

(for a fixed circuit C)The electromotive force round a circuit is proportional to the rate of change of flux of magnetic field, through the circuit. Faradays Law is the basis for electric generators. It also forms the basis for inductors and transformers.

Originates from Ampres (Circuital) Law :

Satisfied by the field for a steady line current (Biot-Savart Law, 1820):

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**1831-1879.1861 Maxwell had the great idea that unified electricity and magnetism. Made astounding prediction that fleeting electric currents could exist not only in conductors but in all materials, even empty space. Fitted everything together into a single theory. Theory predicted that every time a magnet jiggled or an electric current changed, a wave of energy spread out. He found that waves travelled with speed of light. At a stroke unified electricity, magnetism and light. Astonished everyone, proof took 25 years, when Heinrich Hertz produced waves from a spark-gap source and detected them. Now one of the central pillars of our understanding of the universe, and opened the way to 20th century relativity and quantum theory.Maxwell would have been among the worlds greatest scientists even without his work in electricity and magnetism. His influence is everywhere. He introduced statistical methods into physics; he demonstrated the principle by which we see colours and took the worlds first colour photograph. Maxwells demon molecule-sized creature that could make heat flow from a hot to a cold gas was the first effective scientific thought experiment. He stimulated the creation of information theory; he wrote a paper on automated control systems that became the foundation of modern control theory and cybernetics. He showed how to use polarised light to reveal strain patterns in a structure; he was the first to suggest a centrifuge to separate gases. ***Michael Faraday (1791-1867). Apprenticed to a London bookbinder. Became fascinated in science by reading books in the shop. After writing to Davy, was given a job as a lab assistant at the Royal Institution. Became a skilled Chemist. In 1823 discovered that chlorine could be liquefied, also discovered benzene. Discovered e/m induction in 1831. His work laid the foundations of all subsequent e/m, leading to devices such as the transformer and electric motor. Was one of the greatest scientific lecturers of the age. Often said to be the greatest experimentalist in the history of science.*Andre Marie Ampere (1775-1836), son of a wealthy family from Lyon in France. Did not attend formal school, but was taught at home, mainly by his father. Claimed to have mastered all known mathematics by the age of 12. Submitted first paper at age of 13 (as he was unaware of calculus, this was not thought worthy of publication). Family was badly hit by French revolution (sister died, father guillotined). Became Prof. of Physics and Chemistry at Bourg Ecole Centrale in 1802. Published treatises on Mathematical Theory of Games and Calculus of Variations (1803). Appointed tutor at Ecole Polytechnique in Paris in 1804. Professor in 1809, chair at Universite de France in 1826. Disastrous marriage 1806, separated 1807. Worked on partial differential equations, chemistry (fluorine, classification of elements); theory of light (refraction, advocate of wave theory) and a combined theory of electricity and magnetism, produced very quickly after hearing of the Danish physicist Orsteds experimental work. Discovered electrodynamical forces between linear wires. Similar work also done by Biot and Savart, and by Poisson. Amperes most important publication, Memoir on the Mathematical Theory of Electrodynamic Phenomena, was published in 1826, and his theories became fundamental for 19th century developments in electricity and magnetism. Also discovered induction 9 years before Faraday but let the latter have full credit. Amperes son achieved fame as a historian, his daughter married one of Napoleons lieutenants, who became an alcoholic and the marriage disintegrated acrimoniously.

Biot: 1774-1862, Paris.Education at Louis-Le-Grand, followed by the army. Took part in insurrection against government, captured but released after pleadings by Monge. Professor of Mathematics at Beauvais, then at College de France (thanks to Laplace). 1809 Professor of Astronomy in Spain. Made advances in astronomy, elasticity, electricity and magnetism, heat and optics; mathematical work in geometry. Together with Savart, discovered that intensity of magnetic field set up by a current in a wire varies inversely with the distance from the wire. Awarded the Rumford Medal of the Royal Society for his work on the polarisation of light passing through chemical solutions.*