1. The problem statement, all variables and given/known data http://img99.imageshack.us/img99/763/prob45.gif [Broken] Fig. 1 and 2 show a dielectric slab being inserted between the plates of one of two identical capacitors, capacitor 2. Select the correct answer to each of the statements below (enter I for `increases', D for `decreases', or S for `stays the same'). In Fig. 2, the potential difference between the plates of capacitor 2 _______ when the dielectric is inserted. In Fig. 2, the charge on capacitor 1 _______ when the dielectric is inserted. In Fig. 1, the capacitance of capacitor 2 _______ when the dielectric is inserted. In Fig. 1, the potential energy stored in capacitor 1 _______ when the dielectric is inserted. 2. Relevant equations ΔV = Q1/C1 = Q2/C2 ( parallel ) Ceq = C1 + C2 ( parallel ) C = Cok Q is distributed evenly over two capacitors in series. 3. The attempt at a solution A. Stays the same. ΔV over a capacitance in parallel always remains the same. B. ΔV = Q1/C1 = Q2/C2, when C2 increases (C = Cok), Q2 will increase as well to compensate. Qnet = Q1 + Q2, this means Q1 must decrease. C. C = Cok, therefore C increases. D. 1/Ceq = 1/C1 + 1/C2. when C2 grows larger, 1/C2 grows smaller resulting in a smaller C1. V1 = Q2/(2*C). I've revised this many times and I still can't see what I'm doing wrong. Any help muchly appreciated, thanks!