A straight, nonconducting plastic wire 8.50 cm long carries a charge density of 100 nC/m 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 6.00 cm directly above its midpoint.
b) 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 6.00 cm directly above its center.