Two 4.0cm × 4.0cm square aluminum electrodes, spaced 0.50mm apart are connected to a 300V battery.

What is the charge on the positive electrode?

I already found the capacitance which turned out to be 28 pF.

Isn't Capacity=coulombs/volt ? figure the coulombs of charge.

This is my full work...

First I had to find the capacitance so,

C=[(8.85*10^-12)(.04)^2]/.0005
=2.832*10^-11 F
=28.32 pF

Now I have to find the charge on the positive electrode, so i tried

Q=CV
=(28*10^-12)(300V)
=8.0*10^-9

but it's wrong

How do you get 28*300 to be 8.0 ?

Generally, we get 7.6 times some power of ten.

oops, 8.6 x some power of ten

I have no idea, that's what my calculator is coming up as when i type in

(28*10^-12)(300)

and since my homework is asking for 2 sig figs, i put 8.0

are you sure 8.6?? i'm getting 8.4

nvm bob, i figured it out and got it right on my homework thanks for your help!

add a pi

yes! that's exactly what I thought. So i ended up figuring that out and got 2.8*10^-9 coulombs but somehow it's still wrong

How can 300*28Pico be 2.8 times some power? It has to be 7.6 as the numerals.