Electric Field Between Oppositely Charged Parallel Plates

[Soaring Crane]

Homework Statement

An infinite plane of charge with surface charge density sigma = 8.00 nC/m^2 lies in the yz plane at the origin, and a second infinite plane of charge with surface charge density sigma = -8.00 nC/m^2 lies in a plane parallel to the yz plane at x = 4.00 m. The electric field at x = 3.50 m is approximately



a.226 N/C
b.339 N/C
c.904 N/C
d.452 N/C
e.zero

Homework Equations

E = sigma/epsilon_0 for oppositely charged parallel plates

The Attempt at a Solution

E = sigma/epsilon_0 = (8.00*10^-9 C/m^2)/(8.85*10^-12) = 904 N/C ?

Homework Statement

An infinite plane of charge with surface charge density sigma = 8.00 nC/m^2 lies in the yz plane at the origin, and a second infinite plane of charge with surface charge density sigma = -8.00 nC/m^2 lies in a plane parallel to the yz plane at x = 4.00 m. The electric field at x = 5.00 m is approximately

a.226 N/C
b.339 N/C
c.904 N/C
d.452 N/C
e.zero

Homework Equations

See below.

The Attempt at a Solution

If one draws a diagram for the E (and F) vectors, the vectors cancel each other out when outside the space between the plates, so it is 0?

Thanks.

 

[Doc Al]

It's all good. (I didn't check your arithmetic for the first one, but your method is correct.)