A straight, nonconducting plastic wire 9.00 long carries a charge density of 100 distributed uniformly along its length. It is lying on a horizontal tabletop. (A) Find the magnitude and direction of the electric field this wire produces at a point 4.00 directly above its midpoint.
(B) upward or downward
(C) If the wire is now bent into a circle lying flat on the table, find the magnitude and direction of the electric field it produces at a point 4.00directly above its center.
(D) upward or downward