1) A positive charge of 18nC is evenly distributed along a straight rod of length 4.0 m that is bent into a circular arc with a radius of 2.0 m. Find the magnitude of the electric field at the center of curvature of the arc?
2) Two infinite-plane nonconducting thin sheets of uniform surface 13µC/m2 and -9µC/m2 are parallel to each other and 0.2 m apart. What are the electric fields between the two sheets and outside of them?. Please help me answer these two questions.