# E-field at various points from two large sheets

1. Feb 26, 2010

### Linus Pauling

E-field at various points from two "large" sheets

1.You've hung two very large sheets of plastic facing each other with distance d between them, as shown in the figure . By rubbing them with wool and silk, you've managed to give one sheet a uniform surface charge density n1 = -n_o and the other a uniform surface charge density n2 = 3n_o .

2. electric field equations

3. Ok, I know that since both sheets are "large" that their field strength is uniform and independent of distance. Thus, point 1, for example, I would just add the -n_0 and 3n_o since the field vectors for the left plate point to the right for point one and the vectors from the far plate point left... but how do I do this in terms of n_o / epsilon_o? I tried entering a numerical value based on the simple addition I described but its wrong.

2. Feb 26, 2010

### ideasrule

Re: E-field at various points from two "large" sheets

I've no idea what "point one" is, nor which plate is on the left and which is on the right. I think you're on the right track, however. Find the electric field produced by each plate and add them vectorially.

3. Feb 26, 2010

### Linus Pauling

Re: E-field at various points from two "large" sheets

Sorry. Point 1 is the left of the left (-n_o) sheet, point to is in between the two sheets, and point 3 is to the right of the right sheet (3n_o).

4. Feb 26, 2010

### Linus Pauling

Re: E-field at various points from two "large" sheets

5. Feb 26, 2010

### Linus Pauling

Re: E-field at various points from two "large" sheets

Nevermind, I got it. The readings this week were typed up wrong so I hadn't read the right sections. It was simple once I had the equation E_plane = n/2ep_o