Problem 1 A uniformly charged (linear charge density A) insulating rod is bent into the shape of a semicircle as shown below. Find the magnitude of the electric field at point 0, which is the center of the semicircle. :1 Hints: Use the relation 8 = r9, where S is the arc length subtended by the angle 6 and r is the radius. Look for any ,I i symmetry in the problem for | l o 0 easier calculation. l