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Unformatted text preview: capacitor with the smaller C has the larger V. IDENTIFY:! The two capacitors are in parallel so the voltage is the same on each, and equal to the applied voltage Vab . SET UP:! Do parts (a) and (b) together. The network is sketched in Figure 24.17. EXECUTE:! V1 # V2 # V V1 # 52.0 V V2 # 52.0 V Figure 24.17 C # Q / V so Q # CV Q1 # C1V1 # . 3.00 \$ F /. 52.0 V / # 156 \$ C. Q2 # C2V2 # . 5.00 \$ F / . 52.0 V / # 260 \$ C. EVALUATE:! To produce the same potential difference, the capacitor with the larger C has the larger Q. 24-6 Chapter 24 24.18. IDENTIFY:! For capacitors in parallel the voltages are the same and the charges add. For capacitors in series, the charges are the same and the voltages add. C # Q / V . SET UP:! C1 and C2 are in parallel and C3 is in series with the parallel combination of C1 and C2 . EXECUTE:! (a) C1 and C2 are in parallel and so have the same potential across them: Q2 40.0 " 10!6 C # # 13.33 V . Therefore, Q1 # V1C1 # (13.33 V)(3.00 " 10!6 F) # 80.0 " 10!6 C . Since C3 is C2 3.00 " 10!6 F in series with the parallel combination of C1 and C2 , its charge must be equal to their combined charge: V1 # V2 # 24.19. 24.20. C3 # 40.0 " 10!6 C 0 80.0 " 10!6 C # 120.0 " 10!6 C . 1 1 1 1 1 (b) The total capacitance is found from and Ctot # 3.21 \$ F . # 0 # 0 !6 Ctot C12 C3 9.00 " 10 F 5.00 " 10!6 F Q 120.0 " 10!6 C Vab # tot # # 37.4 V . Ctot 3.21 " 10!6 F Q 120.0 " 10!6 C EVALUATE:! V3 # 3 # # 24.0 V . Vab # V1 0 V3 . C3 5.00 " 10!6 F IDENTIFY and SET UP:! Use the rules for V for capacitors in series and parallel: for capacitors in parallel the voltages are the same and for capacitors in series the voltages add. EXECUTE:! V1 # Q1 / C1 # .150 \$ C / / . 3.00 \$ F / # 50 V C1 and C2 are in parallel, so V2 # 50 V V3 # 120 V ! V1 # 70 V EVALUATE:! Now that we know the voltages, we could also calculate Q for the other two capacitors. 1 1 1 !A IDENTIFY and SET UP:! C # 0 . For two capacitors in series, #0 . Ceq C1 C2 d...
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## This document was uploaded on 03/11/2014 for the course PHYSICS 240 at University of Michigan.

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