Electromagnetic 1 Chapter 5 Steady electric currents Conduction currents : Drift motion of conduction electrons of holes in conductor or semicond. Electrolytic currents : Migration of positive or/negative ions. Convection currents : Motion of elections ions in vacuum. Kirchhoffs voltage law : Electromotive force Kirchhoffs current law : Conservation of charge Ohms law : V=IR Electromagnetic Current Density & Ohms law (Volume) current density free charge per unit volume convection current density Electromagnetic 3 Ex 5-1 Electromagnetic 4 , Poissons Equation * child langmuir law Electromagnetic 5 * (e p ion) ( ) [point form] of ohms law : ohms law Electromagnetic 6 Point form ohms law Potential Difference of terminals is length cross-section Point form ohms law derive Ckt ohms law Electromagnetic 7 Ex 5-2 Sol : Conductance (G) a) ( ) b) ( ) Electromagnetic Electromotive Force & Kirchhoffs voltage Law static electric field ohms law The source of the nonconservative field Electric battery,. Impressed electric field intensity Electromotive force V Inside source outsideinside outside Electromagnetic 9 Ohms Law Charge cumulation Chemical action k R Kirchhoffs voltage Law Electromagnetic Equation of Continuity and Kirchhoffs Current Law Principle of conservation of charge Current leaving the region = total outward flux of Divergence Theorem equation of continuity Electromagnetic 11 Steady currents,, Kirchhoffs current Law relaxation time Conductor Electromagnetic Power Dissipation & Joules Low work Power drift velocity Total power : point functionPower density under steady-current Joules Law Electromagnetic 13 dsdl A constant cross-section Electromagnetic Boundary conditions for current density Steady current DifferentialIntegral Electromagnetic 15 Ex 5-3 Electromagnetic 16 Steady current flows 2 lossy dielectrics 1 2 Electromagnetic 17 Ex 5-4 : static charge & steady current surface charge upper lower Interface surface charge Electromagnetic Resistance Calculations capacitance ohms Law resistance Electromagnetic 19 Ex 5-5 Electromagnetic 20 R 1. , 2. V 3. 4. 5. Electromagnetic 21 Ex 5-6 Cylindrical coordinate Laplaces equFind total current