Homework Help: Electric Field between two positivly chared surfaces

1. Jan 21, 2008

ghetto_bird25

1. The problem statement, all variables and given/known data
Figure 24-34 shows cross-sections through two large, parallel, nonconducting sheets with identical distributions of positive charge with surface charge density σ = 2.62 x 10-22 C/m2. What is the y component of the electric field at points (a) above the sheets, (b) between them, and (c) below them?
http://edugen.wiley.com/edugen/courses/crs1141/art/qb/qu/c24/Fig23_38.gif

2. Relevant equations
E=$$\sigma$$/$$\epsilon$$

3. The attempt at a solution
my question is how would u find the y component as when using the equation you get E? would you use trig or is there another way?

2. Jan 21, 2008

Dick

There is ONLY a y component from each plate, isn't there? Just ask yourself in each region whether the E fields add or subtract. No trig needed.

3. Jan 21, 2008

ghetto_bird25

ic...just one quick question, does the rule for cylinders apply for this question so that the center has a net electric field of 0?

4. Jan 21, 2008

Dick

Compute the E fields on each side, consider direction and add them. There is no automatic rule telling you that the E field in the middle is zero.