# Calculating Electric field and total charge

1. Sep 14, 2011

### ee1215

1. The problem statement, all variables and given/known data
Surface charge density on gold plate of radium 15cm is 5x10^-9 C/m^2
A) Calculate electric field intensity (E) near plate center
B) Assuming surface charge density is constant over the entire surface of the plate, calculate the total charge on the plate

2. Relevant equations
En=$\rho$ / $\epsilon$

3. The attempt at a solution
A) En=5x10^-9 C/m^2 / 8.85x10^-12 = 565 V/m
B) Not sure on the total charge equation.

2. Sep 16, 2011