1. MIDTERM 1 UTC 4.132 Thu-Sep 27, 7:00PM - 9:00PM Course Summary Unit 1 Provided Bring pencils, calculators (memory cleared)

2. Question 1 A.a uniformly charged long rod. B.a uniformly charged ring. C.a uniformly charged disk. D.a point charge. Which one of these statements is true? When near the center of the object, the electric field hardly changes with increasing distance from

3. Question A.The electric field inside both balls is zero. B.The electric field inside the metal ball is zero, but it is nonzero inside the plastic ball. C.The electric fields inside both objects are nonzero and are pointing toward each other. D.The electric field inside the plastic ball is zero, but it is nonzero inside the metal ball. A solid metal ball carrying negative excess charge is placed near a uniformly charged plastic ball. Which one of the following statements is true? -Q+Q metalplastic

4. Review 1) Vector Arithmetic 2) Electric Force and Field of a Charged Particle -Q

5. x y Review 3) Dipoles Electric field of a dipole Forces on a dipole Electric field due to something else. Calculate force on each Charge from – to + -Q +Q

6. Review 4) Induced Dipoles – + Example: Force between charge and induced dipole

7. Review 4) Polarization of Metals and Insulators Metal Insulator Neutral + Metal Insulator Excess + + + ++ + ++ + + + + What is E inside metal in static equilibrium?

8. General Procedure for Calculating Electric Field of Distributed Charges 1.Cut the charge distribution into pieces for which the field is known 2.Write an expression for the electric field due to one piece (i) Choose origin (ii) Write an expression for  E and its components 3.Add up the contributions of all the pieces (i) Try to integrate symbolically (ii) If impossible – integrate numerically 4.Check the results: (i) Direction (ii) Units (iii) Special cases

9. Review 6) Flux and Gauss’ Law Examples: Spherical Shell, Long Rod, Large Sheet

10. Review 6) Gauss’s Law and Metals Examples: Neutral Metal Solid with Void; Charge in Void Use E=0 inside metals 7) Superposition Example: Large Sheet and Infinite Rod X X X

11. ROOM CHANGE FOR MIDTERM 1 UTC 4.132 Thu-Sep 27, 7:00PM - 9:00PM