tailieunhanh - Electromagnetic Field Theory: A Problem Solving Approach Part 27

Electromagnetic Field Theory: A Problem Solving Approach Part 27. Electromagnetic field theory is often the least popular course in the electrical engineering curriculum. Heavy reliance on vector and integral calculus can obscure physical phenomena so that the student becomes bogged down in the mathematics and loses sight of the applications. This book instills problem solving confidence by teaching through the use of a large number of worked problems. To keep the subject exciting, many of these problems are based on physical processes, devices, and models. This text is an introductory treatment on the junior level for a two-semester electrical engineering. | Problems 235 I E r d r d E r P2 f p y b M b Find the force on dipole 1 due to dipole 2 when the two dipoles are colinear or are adjacent a distance a apart. c Find the force on dipole 1 if it is the last dipole in an infinite array of identical colinear or adjacent dipoles with spacing a. Hint l n4 ir4 90. 10. A point dipole with moment it is a distance D from the center of a grounded sphere of radius R. Hint d . a What is the induced dipole moment of the sphere b What is the electric field everywhere along the z axis c What is the force on the sphere Hint See Problem 9a. Section 3-2 11. Find the potential electric Held and charge density distributions for each of the following charges placed within a medium of infinite extent described by drift-diffusion conduction in the limit when the electrical potential is much less than the thermal voltage qVIkT 1 a Sheet of surface charge oy placed at x 0. b Infinitely long line charge with uniform density A. Hint Bessel s equation results. c Conducting sphere of radius R carrying a total surface charge Q. 236 Polarization and Conduction 12. Two electrodes at potential Vo 2 located at x l enclose a medium described by drift-diffusion conduction for two oppositely charged carriers where qVotkT 1. a Find the approximate solutions of the potential electric field and charge density distributions. What is the charge polarity near each electrode b What is the total charge per unit area within the volume of the medium and on each electrode 13. a Neglecting diffusion effects but including charge inertia and collisions what is the time dependence of the velocity of charge carriers when an electric field oix is instantaneously turned on at t 0 b After the charge carriers have reached their steadystate velocity the electric field is suddenly turned off. What is their resulting velocity c This material is now placed between parallel plate electrodes of area A and spacing s. A sinusoidal voltage is applied Re Vo e1 - What is the .