2. There are three infinite planes with uniform charge density, s1, s2, and s3, positioned as below.
(a) Calculate the electric field everywhere assuming the planes are in free space.
(b) Calculate the electric field everywhere assuming the planes are encased in plastic (er = 2).
3. Calculate the electric field along the axis of a uniformly charged (so) disk.
4. A uniformly charged ring with line density lo is suspended above a semi-infinite, grounded, metal plane. Calculate the potential and electric field on the axis of the ring.