1. The problem statement, all variables and given/known data In lab we did an experiment where there was a 12v D.C. power supply in a glass dish filled with water. We set the + and - terminals in the dish and a piece of graph paper underneath. With a volt-meter we hunted for certain electric potentials such as 2V, 4V, 0V, etc and wrote down the co-ordinates. This was then plotted, and we were told to draw the electric field. Basically a dipole. No big deal. Then the professor offered us a lucrative opportunity for extra-credit which I can't resist because the class is difficult and I want to learn how to do things like this. The question is: For what charge Q could replace the 12V power source. This was all fine and dandy but I am sure I've made a mistake somewhere in my math. Not asking for an answer by the way. Any hints or ideas would be greatly appreciated! 2. Relevant equations ∇V = -E 3. The attempt at a solution See attached files. Edit by the way: I only show my result for the i vector componant because I did the Y similarly. I later took the magnitude of the resultant q vector for my answer.