Originally Posted by

**heathrowjohnny** Find the potential a distance $\displaystyle s $ from an infinitely long straight wire that carries a uniform line charge $\displaystyle \lambda $.

So $\displaystyle \bold{E} = \frac{1}{4 \pi \epsilon_{0}} \frac{2 \lambda}{s} \bold{\hat{s}} $. Mr F says: Correct (and there's an obvious trivial simplification). I hope you used Gauss's Law!

So you can't set the reference point at $\displaystyle \infty $ because the charge extends out to $\displaystyle \infty $.

So is it $\displaystyle V(s) = -\int_{a}^{s} \left(\frac{1}{4 \pi \epsilon_{0}} \frac{2 \lambda}{s} \right) ds = -\frac{1}{4 \pi \epsilon_{0}} 2 \lambda \ln \left(\frac{s}{a} \right) $?