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Announcements. Homework for tomorrow… (Ch . 29, Probs. 24, 52, & 53) CQ2: E x = 0 V/m 29.8: 1.5 V 29.11: see back of book 29.14: a) E x = 0 V/ m b) E x = -200 V/m Office hours… MW 12:30-1:30 pm TR 9-10 am F 10-11 am Tutorial Learning Center (TLC) hours:
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Announcements • Homework for tomorrow… (Ch. 29, Probs. 24, 52, & 53) CQ2: Ex = 0 V/m 29.8: 1.5 V 29.11: see back of book 29.14: a) Ex = 0 V/m b) Ex = -200 V/m • Office hours… MW 12:30-1:30 pm TR 9-10 am F 10-11 am • Tutorial Learning Center (TLC) hours: M 8-1 pm, 3-6 pm, W 8-1 pm, 2-6 pm TR 8-6 pm, F 8-2 pm
Chapter 29 Potential & Field (Combinations of Capacitors & The Energy Stored in a Capacitor)
Review… • Kirchoff’s Loop Rule… • Conductors in Electrostatic Equilibrium… • Capacitance…
Forming a Capacitor… • 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.
i.e. 29.6: Charging a capacitor The spacing between the plates of a 1.0 μF capacitor is 0.050 mm • What is the surface area of the plates? • How much charge is on the plates if this capacitor is attached to a 1.5 V battery?
Combinations of Capacitors Consider two capacitors in parallel… • Can we find an equivalent capacitor, Ceq, to the two capacitors, C1 & C2? + + Ceq C1 C2 - -
Combinations of Capacitors Consider two capacitors in parallel… • Can we find an equivalent capacitor, Ceq, to the two capacitors, C1 & C2? • YES! + + Ceq C1 C2 - -
Combinations of Capacitors What about for several capacitors in parallel? • Can we find an equivalent capacitor, Ceq, to the capacitors, C1 , C2, … (all in parallel)? + + Ceq C1 C2 C3 - -
Combinations of Capacitors What about for several capacitors in parallel? • Can we find an equivalent capacitor, Ceq, to the capacitors, C1 , C2, … (all in parallel)? • YES! + + Ceq C1 C2 C3 - -
Combinations of Capacitors Consider two capacitors in series… • Can we find an equivalent capacitor, Ceq, to the two capacitors, C1 & C2? + + C1 Ceq C2 - -
Combinations of Capacitors Consider two capacitors in series… • Can we find an equivalent capacitor, Ceq, to the two capacitors, C1 & C2? • YES! + + C1 Ceq C2 - -
Combinations of Capacitors What about several capacitors in series? • Can we find an equivalent capacitor, Ceq, to the capacitors, C1 , C2 ,… (all in series)? C1 + + Ceq C2 - - C3
Combinations of Capacitors What about several capacitors in series? • Can we find an equivalent capacitor, Ceq, to the capacitors, C1 , C2 ,… (all in series)? • YES! C1 + + Ceq C2 - - C3
Quiz Question 1 The equivalent capacitance is • 9 F. • 6 F. • 3 F. • 2 F. • 1/2 F.
i.e. 29.7:A Capacitor Circuit Find the charge on and the potential difference across each of the three capacitors in the figure below. Given: E = 12 V, C1 = 3 μF, C2= 5 μF, C3= 1 μF C1 + C2 C3 -