Charge and voltage of capacitors?

[gmmstr827]

Homework Statement

Suppose that C1 = C2 = C3 = 16.0 µF and C4 = 28.5 µF. If the charge on C2 is Q2 = 12.4 µC, determine the charge on each of the other capacitors, the voltage across each capacitor, and the voltage Vab across the entire combination.

http://i29.photobucket.com/albums/c261/gmmstr827/capacitor.jpg

Homework Equations

Q=CV

The Attempt at a Solution

C1=C2=C3=16.0 µF, C4=28.5 µF
Q2=12.4 µC

Note that V1=V2, V3=V4, and Q1=Q2

V2=Q2/C2
V2 = 12.4 µC / 16.0 µF
V1 = V2 = 0.775 V

Note that V3 = 2*V2

V3 = 2*0.775 V
V3 = 1.55 V

Q3=C3*V3
Q3 = 16.0 µF * 1.55 V
Q3 = 24.8 µC

Q4 = C4*V4
Q4 = 28.5 µF * 1.55 V
Q4 = 44.175 µC

Therefore
Q1 = Q2 = 12.4 µC
Q3 = 24.8 µC
Q4 = 44.175 µC
V1 = V2 = 0.775 V
V3 = V4 = 1.55 VIs that correct?

 

[gneill]

You were doing fine until you ran up against Q4. Take a close look at what you've written.

 

[gmmstr827]

You were doing fine until you ran up against Q4. Take a close look at what you've written.

Guess I didn't hit the Ctrl+C hard enough that time and pasted the previous thing. I fixed it. The numbers all work out though I believe?

 

[SammyS]

V₃≠v₄

Use conservation of charge to find how Q₄ is related to the other charges.