Question

A thin spherical metallic shell of radius 0.07m has a surface charge density of 21 µCm-2 .Determine the electric field strength and potential and the following positions:-
0.01m away from the centre of the shell
At the surface of the shell

Answer 1

ok i need some help with this question i used Gauss's Law the determine an equation but i'm not sure if its 100% correct.

\[\int\limits_{?}^{?} E.dA = 4\Pi kq\]
\[EA = 4 \Pi kq \]
where \[q = \sigma A\]
therefore :- \[E = 4\Pi k \sigma\]

so am i going correct some how i feel that i'm doing something wrong with this question could someone plz help me out thx!

Answer 2

What you've done is correct for the surface of the shell, but - assuming there is no charge inside the shell) the electric field would be 0 because there is no charge enclosed within the Gaussian surface of radius 0.01m.
Of course you haven't addressed the electric potential yet either...

Answer 3

oh thanks. The electric potential would you care to elaborate about it idk to do for that part of the question thx.