1. The problem statement, all variables and given/known data http://i215.photobucket.com/albums/cc95/warrenm_2007/elec.jpg Here is the problem: The red dots represent points of equal electric potential and the gray haze is the projected equipotential line. I am unsure about what happens to the electric field lines as they encounter the insulator and around the large conductor in the middle. If anyone could explain to me what is happening there, I would appreciate it. 2. Relevant equations 3. The attempt at a solution I guess I would think that the insulator stops the electric field and that it does not transmit to the other side. It would I believe stop the electric field and given that there is no source for an electric field on the other side, I don't see why it would continue. Around the large conductor in the middle, I would think that the electric field lines are feeding into the conductor unless they can go up the middle or around it to continue to the other side. Also: does the insulator affect the field at all? The one point I have on the surface of the insulator looks a little fishy. Thanks in advance for any help or advice.