1. The problem statement, all variables and given/known data In the arrangement shown in the figure below, a potential difference DeltaV is applied, and C1 is adjusted so that the voltmeter between points b and d reads zero. http://capa.physics.mcmaster.ca/figures/sb/Graph26/sb-pic2667.png [Broken] This "balance" occurs when C1 = 3.56 µF. If C3 = 9.50 µF and C4 = 12.3 µF, calculate the value of C2 2. Relevant equations CΔV=Q 3. The attempt at a solution I know that capacitor 1-2, 3-4 is connected in series and the charge on capacitors 1-2, 3-4 are the same because the voltmeter reads zero which mean there's no transfer of electrons between the plates so the charge of the capacitors connected in series should be the same. I came up with the following attempt: 1: C(equivalent 1-2)=(1/C1)+(1/C2) 2:C(equivalent 3-4)=(1/C3)+(1/C4) 3:C(total)= C(equivalent 1-2)+C(equivalent 3-4) 4:Qtotal=Q1+Q2 5:Qtotal= ΔV(C(equivalent 1-2)+C(equivalent 3-4)) When i got step 5, i realized everything just cancels out... lol so where did I go wrong in my approach?