How to solve for the capacitance of an interlocking plates

[mba444]

Homework Statement

A capacitor is constructed of interlocking
plates as shown in the figure (a cross-sectional
view). The separation between adjacent
plates is 1.26 mm, and the effective area of
one of the adjacent plates is 6.1 cm2.

http://images.upload2world.com/get-6-2009-upload2world_com_jdqtdnhw.jpg

The permittivity of a vacuum is 8.85419 × 10−12 C2/N · m2.
Ignoring side effects, calculate the capaci-
tance of this unit. Answer in units of pF.

Homework Equations

C=(Eo*A)/d

The Attempt at a Solution

what i did is that i assumed that the capacitors are parrallel therefore i used this equation by plugging the given values .. but still i keep getting the wrong answer ..

i am looking forward for your help
thanx in advance

 

[drizzle]

hey mba444, welcome to PF :)
how many capacitors you assumed that are parrallel?

 

[mba444]

thanx for welcoming

2

 

[drizzle]

sure not, you know that each capacitor have two plates separated by the vacuum now look again at the pic, got it?!...

 

[mba444]

Ohhh

thereore 8

thanx a lot :shy: