I need help trying to set up this problem. I want to find the capacitance between a point charge and a finite plate (or disk) as the point moves from above the center of the plate to some distance off the plate. I have been able to simulate this problem using FEM, however, there should be a way to solve this by using Gauss's law. In the simulated model I used a potential difference of 1 V between the plate and point. I don't know if this forms an actual capacitor or if it is a self-capacitance of the plate with the point charge inducing a surface charge distribution on the plate. Any insight into this problem would be helpful.