# Calculating Potential from electric field problem

1. Sep 20, 2008

### th3plan

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

An infinite, nonconducting sheet has a surface charge density σ = +8.77 pC/m2. (a) How much work is done by the electric field due to the sheet if a particle of charge q0 = 9.61 x 10-19 C is moved from the sheet to a point P at distance d = 2.45 cm from the sheet? (b) If the electric potential V is defined to be zero on the sheet, what is V at P?

Shouldnt the answer for part a be negative, because the solution manual says its positive,. I know V=-W$$_{}infty$$/q . Can someone explain me why this is so ?

2. Sep 20, 2008

### Redbelly98

Staff Emeritus