Two identical closely spaced circular disks form a parallel-plate capacitor. Transferring 2.2×109 electrons from one disk to the other causes the electric field strength between them to be 1.3×105
N/C
.What are the diameters of the disks?

Question

Two identical closely spaced circular disks form a parallel-plate capacitor. Transferring 2.2×109 electrons from one disk to the other causes the electric field strength between them to be 1.3×105 
N/C
.What are the diameters of the disks?

irishboy123 · Answer

what formulae do you know??

i can roll with $C = \dfrac{\epsilon_o A}{d}  = \dfrac{Q}{V}$

$ A  = \dfrac{Q d}{\epsilon_o V}$

And the electric field in parallel plates is $E = \dfrac{ V}{ d}$

So....

$ A  = \dfrac{Q }{\epsilon_o E}$

you've got those numbers, i reckon

dricohernandez · Answer

Q/4πεod²

irishboy123 · Answer

$D = \sqrt{  \dfrac{4Q}{\pi \epsilon_o E}  } $

irishboy123 · Answer

As in 

$A =  \dfrac{\pi D^2}{4}$

dricohernandez · Answer

so what would the answer be?

irishboy123 · Answer

no idea mate, i'd need to find a calculator