You have two disks, both with a radius of 25mm, and both made of the same non-conducting material. Both disks are uniformly charged. Disk 1 has a charge of 1.5 μC and the total charge of disk 2 is unknown. You place disk 1 at Z1 = 0mm and disk 2 at Z2= 32mm. The symmetry axis of each disk coincides with the z-axis. Using a small charged ball you discover that the electric force is equal to zero at Z=88mm. What is the charge on disk 2?