1. The problem statement, all variables and given/known data The capacitors in the figure are initially uncharged and are connected, as in the diagram, with switch S open. The applied potential difference is V_ab = 210V. a) What is the potential difference V_cd? b) What is the potential difference across each capacitor after switch S is closed? c) How much charge flowed through the switch when it was closed? 2. Relevant equations 1/C_eq = 1/C1 + 1/C2 C_eq = Q_total/V 3. The attempt at a solution So, as a side note, I'm calling the top left capacitor C_1. Top right is C_2. Bottom left is C_3, and bottom right is C_4. Here's what I've got so far... With the switch open, taking C_1 and C_2 to be a series of capacitors, and C_3 and C_4 to be a separate series, I calculated C_eq for both (getting the same value, of course) and adding them to get C_total, 4*10^-6 F. From there, using Q_total = C_eq*V, I solved for Q, getting 8.4 *10^-4. So if I'm understanding correctly, this Q is as a result of all 4 capacitors and the given potential of 210 V. That being said, I would think my next step would be to divide that value by 4 (for each capacitor) to obtain the charge of each individual capacitor, but this turns out to be wrong, and I don't understand why. Once I have the charge for each capacitor, I should be able to calculate V_cd by considering C_1 and C_3 to be part of a parallel system, and use V=Q/C, where Q is the charge of either capacitor (they should be the same in this case, I think?) and C is either C_1 or C_3. At this point, I'm stuck on the the charge Q of each capacitor. If anyone could help clear that up for me, I would really appreciate it. Thank you!