1. The problem statement, all variables and given/known data Find electric potential at a center of charged rod with charge 'Q' and length '2a' if referent point is at infinity. 2. Relevant equations Electric potential of a point charge: V=kQ/r Electric potential via electric field: integral (Edl) 3. The attempt at a solution I used relation for potential of point charge: V=kQ/(1/r_A-1/r_B), where r_A is a distance between charge and point, and r_B is the distance of infinity. From there, I think that r_A=a because that is the maximum distance between point and charge (point lies on the rod). This gives V=kQ/a Is it right that if we calculate potential of this rod in a given point, where referent point is at infinity, we can look at the rod as a point charge? Could someone show the steps if this isn't correct? Thanks for replies.