# 3 batteries and 3 capacitors

1. Oct 19, 2011

### sabak22

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

Three capacitors C1–C3, all initially uncharged, are placed in the circuit show above. The capacitances are C1=15.2 μF, C2=9.8 μF, C3=4.4 μF, and the battery voltages are V1=20 V, V2=20 V, V3=5 V.

What is the magnitude q1 of the charge on capacitor C1 once equilibrium has been established?

What is the magnitude q2 of the charge on capacitor C2 once equilibrium has been established?

What is the magnitude q3 of the charge on capacitor C3 once equilibrium has been established?

2. Relevant equations

V=Q/C
I1+I3=i2

3. The attempt at a solution

I tried applrying the kirchhoff's rule, but i dont know where to go with it... i dont even know if i am write or not.
V1+Q1/C1 + Q2/C2+V2=0
V3+Q2/C2+V2+Q3/C3=0

#### Attached Files:

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Last edited: Oct 19, 2011
2. Oct 19, 2011

### SammyS

Staff Emeritus

3. Oct 19, 2011

### sabak22

really sorry about that. I didnt realise

4. Oct 20, 2011

### SammyS

Staff Emeritus
For the loop with V1+Q1/C1 + Q2/C2+V2=0: Assuming the voltage drops are for traversing the loop in a Clockwise sense, there is a voltage drop across the capacitors. This equation should be:
V1 - Q1/C1 - Q2/C2 + V2=0 .​

Similarly, the signs for the voltages across the capacitors in the other loop equation should also be changed.

Additionally, you have Q1 + Q3 = Q2, because I1 + I3 = I2 .

Plugin all the values, do some algebra and see what you get.