1. Announcements  Homework for tomorrow… Ch. 29: Probs. 20, 22, & 54 CQ5: accelerates right CQ6: a) V a >V b b) ΔV ab <ΔV cd <ΔV ef c) yes, no 29.8: 1.5 V 29.12: E x (0cm<x<2cm) = +2,500 V/mE x (2cm<x<3cm) = -10,000 V/m 29.15: a) 27 V/mb) 3.7 V/m  Office hours… MW 12:30-1:30 pm TR 9-10 am F 1-2 pm  Tutorial Learning Center (TLC) hours: MW 8-10 am, 12-6 pmR 8-12 pm, 2-6 pm T 8-1 pm, 2-6 pmF 8-10 am, 2-5 pm

2. Chapter 29 Potential & Field (Combinations of Capacitors)

3.  Kirchoff’s Loop Rule…  Conductors in Electrostatic Equilibrium…  Capacitance… Review…

4.  Any two electrodes, regardless of their shape, form a capacitor.  The capacitance of two electrodes is..  and depends only on the geometry of the electrodes. Forming a Capacitor…

5. The spacing between the plates of a 1.0 μF capacitor is 0.050 mm a. What is the surface area of the plates? b. How much charge is on the plates if this capacitor is attached to a 1.5 V battery? i.e. 29.6: Charging a capacitor

6. Consider two capacitors in parallel…  Can we find an equivalent capacitor, C eq, to the two capacitors, C 1 & C 2 ? Combinations of Capacitors + - C1C1 C2C2 + - C eq

7. Consider two capacitors in parallel…  Can we find an equivalent capacitor, C eq, to the two capacitors, C 1 & C 2 ?  YES! Combinations of Capacitors + - C1C1 C2C2 + - C eq

8. What about for several capacitors in parallel?  Can we find an equivalent capacitor, C eq, to the capacitors, C 1, C 2, … (all in parallel)? Combinations of Capacitors + - C1C1 C2C2 + - C eq C3C3

9. What about for several capacitors in parallel?  Can we find an equivalent capacitor, C eq, to the capacitors, C 1, C 2, … (all in parallel)?  YES! Combinations of Capacitors + - C1C1 C2C2 + - C eq C3C3

10. Consider two capacitors in series…  Can we find an equivalent capacitor, C eq, to the two capacitors, C 1 & C 2 ? Combinations of Capacitors + - C1C1 C2C2 + - C eq

11. Consider two capacitors in series…  Can we find an equivalent capacitor, C eq, to the two capacitors, C 1 & C 2 ?  YES! Combinations of Capacitors + - C1C1 C2C2 + - C eq

12. What about several capacitors in series?  Can we find an equivalent capacitor, C eq, to the capacitors, C 1, C 2,… (all in series)? Combinations of Capacitors + - C1C1 C2C2 + - C eq C3C3

13. What about several capacitors in series?  Can we find an equivalent capacitor, C eq, to the capacitors, C 1, C 2,… (all in series)?  YES! Combinations of Capacitors + - C1C1 C2C2 + - C eq C3C3

14. The equivalent capacitance is 1. 9  F. 2. 6  F. 3. 3  F. 4. 2  F. 5. 1/2  F. Quiz Question 1

15. Find the charge on and the potential difference across each of the three capacitors in the figure below. Given: E = 12 V, C 1 = 3 μF, C 2 = 5 μF, C 3 = 1 μF i.e. 29.7: A Capacitor Circuit + - C1C1 C2C2 C3C3