1. Sep 7, 2010

### ninjarawr

1. The problem statement, all variables and given/known data

In the circuit below, consisting of a battery and several capacitors, some quantities are known and some are not. The capacitors were completely uncharged before the battery was attached and we are considering the static situation.

Circuit: http://img690.imageshack.us/i/showmepl.gif/

Q1= 8.5 × 10^-6 C
C1= 7.6 × 10^-6 F
C2= 2 × 10^-6 F
Energy stored on C2 is W2= 4.2 × 10^ -6 J

What is the charge Q3 on capacitor C3 ?

3. The attempt at a solution

I've figured out that V1 = 1.12, V2 and V3 = 2.05...but I have no idea how to find Q3 because we don't know C3

2. Sep 7, 2010

### rl.bhat

In the series combination, Charges are the same in all the capacitors.So the charge on C1 is the same as the charge on the parallel combination of C2 and C3. Hence

Q2 = C1V2 and Q2 + Q3 = Q1.

Now find Q3.

3. Sep 7, 2010

### ninjarawr

Thank you man!!

I forgot to add the parallel C2 and C3 and turn it into one circuit, then assume that they are in series with C1.....I really appreciate the help

4. Oct 10, 2010