Electric field outside of conducting sphere.

[ramses07]

Homework Statement

A conducting sphere of radius 0.01 m has a charge of 1.0 × 10–9 C deposited on it. The magnitude of the electric field in N/C just outside the surface of the sphere is

Homework Equations

E=kq/r^2

EA=q/eo

The Attempt at a Solution

I tried the first equation and got 90000, but the answer is 900. I am racking my brains here trying to understand how to find the answer. Its seems simple enough, I am probably just missing a step, can anybody point to what I am doing wrong.

 

[Axiom17]

Could you show your calculations so far? Then can see where you're going wrong.

 

[hikaru1221]

Does the question mention the permittivity of the medium outside the sphere?

 

[Axiom17]

..also I got $E=90000NC^{-1}$ as well. Where did you get that the answer should be $E=900NC^{-1}$? Also check those values you've been given are correct (but they seem OK).