# Homework Help: Infinite Sheet Potential Question

1. Dec 14, 2011

### CH1991

1. The problem statement, all variables and given/known data

Please check picture below or attachment.

http://i.imgur.com/DayoP.png

2. Relevant equations

E=density/2 constant

3. The attempt at a solution

I know, E=density/2 constant, but how do we get potential from eletric field and how do I find it is positive or negative?

Thanks!

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2. Dec 14, 2011

### ehild

Recall that the electric field strength is negative gradient of the potential which is equivalent to say the potential difference VA-VB between points A and B is$$V_B-V_A=-\int_A^B{E_s ds}$$
Find the electric field between the plates first.

ehild

3. Dec 14, 2011

### CH1991

Yeah,I did find E=density/2 constant as my eletric field, but how do I get potential?
Thanks!

4. Dec 14, 2011

### ehild

That is the electric field from the charge distribution of one plate, but you have two plates.

You need the potential difference between the plates.
Have you read my previous post how to get the potential difference?

ehild

5. Dec 14, 2011

### CH1991

You mean #2?
Thanks!

6. Dec 14, 2011

Thank you!