Emft

Electrostatics

1. ELECTROMAGNETIC FIELD THEORY By: G Sambasiva Rao Asst.Prof /ECE Dept.

2. UNIT – I Electrostatics-I: Coulomb’s Law, Electric Field Intensity - Electric Fields due to Continuous Charge Distributions – Line Charge, Surface Charge, Volume Charge - Electric Flux Density - Gauss Law –Applications of Gauss Law – Point Charge, Infinite Line Charge, Infinite Sheet Charge - Electric Potential -Relations Between E and V. Syllabus UNIT – II Electrostatics-II : The nature of dielectric materials, boundary conditions for perfect dielectric materials. Capacitance , Several capacitance examples: Parallel Plate Capacitor, Capacitance of a Coaxial Cable, Spherical Capacitor. Derivations of Poisson’s and Laplace’s equations. Current and current density, Energy density , continuity of current. UNIT – III The Steady Magnetic Field: Biot -Savart’s Law, Ampere’s Circuital Law, Magnetic Flux and Magnetic Flux Density, The scalar and vector magnetic potentials. Magnetic Forces and Materials: Force on a moving charge, force on a differential current element, force between differential current elements, Magnetic Energy, the nature of magnetic materials, magnetization and permeability , magnetic boundary conditions.

3. UNIT – IV Time Varying Fields and Maxwell’s Equations: Faraday’s Law - Transformer and Motional EMFs –Stationary Loop in Time Varying B Field, Moving Loop in Static B Field, Moving Loop in Time VaryingField - Displacement Current – Maxwell’s Equations in Different Final Forms. UNIT – V Wave Equations: Waves equations for: a conducting medium, free space – Relation between E and H in a Uniform plane wave - Wave propagation: Lossless medium, Conducting medium, Good Dielectric, Good Conductor - Poynting Vector and Poynting theorm - Reflection of a Plane wave at Normal Incidence - Reflection of a Plane wave at Oblique. TEXTBOOKS: 1. Matthew N.O. Sadiku , Elements of Electromagnetics, Oxford University Press, 3rd edition, 2008. 2. William H. Hayt Jr. and John A. Buck, Engineering Electromagnetics, Tata McGraw-Hill publications,7th edition, 2006. 3. G S N Raju, Electromagnetic Field Theory and transmission lines, 1st Edition, Pearson Education India , 2005.

4. UNIT-I : Electrostatics -I

5. Key points

6. Two electrons are placed 1m apart.what is the force between them?

7. Electric Fields have a magnitude and direction Vector Quantities Lines go away from positive Lines go toward negative

8. Electric Field Intensity

9. Electric Fields due to Continuous Charge Distributions

10. Electric Field Strength due to Infinite Line Charge

11. Electric Field Strength due to Surface Charge Density

12. FIELD DUE TO VOLUME CHARGE DENSITY ,

13. ELECTRIC FLUX

14. SALIENT FEATURES OF ELECTRIC FLUX 1. It is independent of the medium. 2. The electric field creates a force on a charge and hence the charge moves along a certain path. This path is called the flux line. 3. The force between two charges acts along a certain path. This path is also called the flux line. 4. Magnitude of flux depends only on the charge from which it originates. 5. The flux lines are equal to the charge in Coulombs. 6. Flux line is only an imaginary line. 7. Its direction is the same as that of the electric field.

15. ELECTRIC FLUX DENSITY

16. Problem: If an electric field in free space is given by E = a x + 2 a y + 5 a z V/m, find the electric flux density.

17. Problem 2. A point charge, Q = 10nC is at the origin in free space. Find the electric field at P (1, 0, 1). Also find the electric flux density at P .

18. GAUSS LAW Gauss’s law It states that the net flux passing through any closed surface is equal to the charge enclosed by that surface, that is, Consider a spherical surface which encloses a charge Q at its centre (Fig.)

19. GAUSS LAW IN POINT FORM Gauss’s law in point form states that the divergence of electric flux density is equal to the volume charge density, that is,