A charge of 2.05 µC is uniformly distributed on a ring of radius 8.5 cm. Find the electric field strength on the axis at the following locations.
(a) 1.2 cm from the center of the ring in N/C
(b) 4.0 cm from the center of the ring in N/C
(c) 4.0 m from the center of the ring in N/C
(d) Find the field strength at 4.0 m using the approximation that the ring is a point charge at the origin.
(e) Compare your results for parts (c) and (d) by finding the ratio of the approximation to the exact result.