# Find the electrical field of a Spherical Shell

## Homework Statement

Consider a thin spherical shell of radius 14.0 cm with a
total charge of 32.0 %C distributed uniformly on its
surface. Find the electric field (a) 10.0 cm and (b) 20.0 cm
from the center of the charge distribution.

## The Attempt at a Solution

Stumped...

I figured that the E(r) was the electrical field of the sphere.

I did 9.9E9(32E-9/14^2) (also did it in meters too)

I guess I am just completely lost in this one.

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## Answers and Replies

rl.bhat
Homework Helper
Electric field due to a charged sphere at a distance r is given by
E = (1/4πεo)*Q/r^2
In side the charged sphere, the electric field is .....?

I got it.

10cm < 14cm, so its inside, meaning = 0

20cm > 14cm, so ke(q/r^2) = 8.99E9(32E-9/.2^2) = 7192, so now I just have to look over where I messed up on the order of magnitude

7.192 MN/C from the center... is the answer!

rl.bhat
Homework Helper
In the problem, the charge is given as 32%C. What is that? micro or nano?
If it is micro, the answer will be correct. You will get 7.192*10^6N/C or 7.192MN/C.