A point particle has a charge equal to +2.30 µC and is fixed at the origin. (a) What is the electric potentialV at a point 4.00 m from the origin assuming that V = 0 at infinity? ? kV (b) How much work must be done to bring a second point particle that has a charge of +2.60 µC from the infinity to a distance of 4.00 m from the +2.30-µC charge? ? mJ