# Electromagnetic Theory

IIT Bombay Course , Prof. D.K. Ghosh

### Lecture 1: Scalar field and its Gradient

##### Lecture Details :

Electromagnetic Theory by Prof. D.K. Ghosh,Department of Physics,IIT Bombay.For more details on NPTEL visit http://nptel.ac.in

##### Course Description :

Introduction to Vector Calculus:Spherical and Cylindrical coordinates, gradient, divergence and curl, Laplacian operator - Volume and line integrals, surface integrals, Divergence and Stokes theorem. Dirac delta - function - Electrostatics:Coulombs law; forces and fields; Electric Field and Potential ; Principle of Superposition; idea of a conservative field - Earnshaws Theorem; electric dipoles, field of a dipole, couple and force on a dipole, energy of a dipole; Electric double layers - Gausss law; solutions for simple symmetry, capacitances, field near charged conductor;Conductors in Electrostatic field; Laplace and Poisson equations; uniqueness theorem - Laplaces equation in rectangular coordinates, separation of variables. Laplaces equation in spherical coordinates, Legendre polynomials - Conducting sphere in E field.Method of images; point charge near conducting sphere, line charge near conducting cylinder- Isotropic dielectrics; polarisation charges (ρb;σb) Gausss law; permittivity and susceptibility; properties of vectors D and E;Boundary conditions at dielectric surfaces; relationship between E and P; thin slab in field, Energy of the electrostatic field, stress in a dielectric.

Magnetostatics:Electric current, Lorentz force, motion of charged particle in electric and magnetic field - Force on and between current elements, definition of B and the Amperes law;Gausss law; field, force, torque and energy; magnetic scalar potential, solid angle of a loop;Amperes law, examples; introduction to magnetic vector potential. Field of a small current loop; magnetic dipole, dipole in an external magnetic field, Biot-Savarts law - Magnetic media; magnetization, existence of diamagnetism and paramagnetism; permeability and magnetic susceptibility; properties of B and H; boundary conditions at surfaces;Methods of calculating B and H, magnetizable sphere in uniform field; electromagnets - Faradays law:Emf, electromagnetic induction, Faradays law for a circuit, interpretation of Faradays emf; self-inductance, inductance of long solenoid, coaxial cylinders, parallel cylinders; mutual inductance; transformers; magnetic energy density - Electromagnetic waves:Equation of continuity, displacement current; Maxwells equations; electromagnetic waves, velocity of light; plane waves in isotropic media;Energy density; Poyntings theorem; radiation pressure and momentum; insulating media; plasmas and the plasma frequency, evanescent waves - Characteristic impedance, reflection and transmission at an angle, total internal reflection. Conducting media; skin effect. Guided waves - Introduction to waveguides; TE modes; waveguide equation; cut-off frequency; characteristic impedance;cavity resonators; optical fibre, radiation by an accelerated particle, elements of antenna theory

##### Other Resources

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