Help Me Find the Capacitance: A Stumped Student's Story

[cupid.callin]

Hi again!

I got stuck in this question (Pic), the original question is the fig. 1. I then arranged the charges on the plates (fig 2) and then separated the plates to form three capacitors. Now I just don’t know what the capacitance will be and how to find it!
First I thought to ignore the two plates at 2 ends. Then the two capacitors on right will be in parallal and their resultant in series with the last one… then answer comes out to be 2C/3 … which is wrong!
According to the book’s answer, all three capacitors will be in series, to get capacitance as C/3 …
Please tell me how are three capacitors in series, and can I really ignore the end plates!

 

[cupid.callin]

Please someone help!

 

[ehild]

They are not in series. Your equivalent circuit on the right is correct. Between which points do you need the resultant capacitance?

ehild

 

[cupid.callin]

No, I am telling you they are in series because the net capacitance comes out to be (acc. to book) C/3

 

[cupid.callin]

some help?