A disk with uniform surface charge density = -8.00 C/m is oriented as shown in the diagram below. The field at a distance y from the center of a disk (of radius r) and where & = 8.85 x 10-12 c/(N m) is the permittivity of free space. 20 (1. along its axis is given by E = y +r P (0, y) X (a) If the radius of the disc is 0.420 m, what is the electric field at a location P whose coordinates are (0, 0.155 m)? X magnitude Check your input values and calculations. N/C direction -x axis (b) What is the magnitude of the electric field at a location very close to the disc? (Assume r y.) N/C