(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

http://img65.imageshack.us/img65/5993/clipboard01vk3.jpg [Broken]

2. Relevant equations

Capacitance for series and parallel connected capacitors; C=Q/delta_V, derivations of last formula

3. The attempt at a solution

Part A

C1 and C2 appear to be connected in series. Therefore, use appropriate formulas.

(1/Cs)=(1/3C)+(1/C) = 3C/4 (answer I got is "flipped" here due to the way the formula is stated)

Alright, so we have the equivalent capacitance for C1 and C2. Now move on to C3.

(C1+C2) + C3 appear to be parallel-connected. So,

Cp=(3C/4) + 5C = 23C/4

I also tried 23/4C in case it couldn't read my entry. A preview confirms it is what I intend, and yet it is wrong. Tried different combos, all wrong. I'm certain I did this correct...what did I do wrong here?

Part B

I'm not sure how to even solve this part. I actually guessed on this. At first I thought higher capacitance = more charge storage, but that was wrong.

Anyway, Capacitance = Q/delta_v. So they want charge, so I derive Q=C(delta_V).

delta_V is not provided, so I don't understand what they want. I'm not even sure how I'm supposed to input it... obviously, integer values are what they want.I am clueless on this problem :(

Part C

I understand V2=V3 because they are connected in parallel. Why is V1 bigger than the other two, though?

As far as I can derive, delta_v=Q/C. So, shouldn't a bigger C mean a smaller delta_V? Am I supposed to use the answers I supposedly got in Part B?

Part D

I don't understand. C3 is the last to be charged (am I thinking of this the wrong way?), and so I am thinking it shouldn't have be affecting the other caps at all. Plus, shouldn't the charges on C1 and C2 beequal, because they are connected in series?

EDIT: I thought about it a little more. C2 and C3, connected in parallel, so therefore they "share" a charge. Because of this, If C3 increases, C2 has no choice but to decrease in charge. Since one could argue that C1 is connected to C3 via aseriesconnection, then that would mean charge is the same -thus meaning that if C3's Q increases, C1's charge MUST increase as well. Is that right?

:uhh:

I would really appreciate any assistance! thanks This is also my first post here.

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# Homework Help: Calculating equivalent capacitance, a question

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