1980E1. A thin plastic rod has uniform linear positive-charge density λ. The rod is bent into a semicircle of radius R as shown above.
a. Determine the electric potential Vo at point 0 , the center of the semicircle.
b. Indicate on the diagram above the direction of the electric field at point 0 . Explain your reasoning.
c. Calculate the magnitude Eo of the electric field at point 0 .
d. Write an approximate expression, in terms of q,Vo, and Eo, for the work required to bring a positive point charge q from infinity to point P , located a small distance s from point O as shown in the diagram above.