1. The problem statement, all variables and given/known data http://online.physics.uiuc.edu/cgi/courses/shell/common/showme.pl?courses/phys212/oldexams/exam1/sp08/fig4.gif [Broken] Two curved rods each have charge +Q uniformly distributed over their length. Which statement best describes the electric field due to these two rods at the midpoint between the two rods marked by an X ? (a) E points up. (b) E points down. (c) E = 0. 2. Relevant equations It's more like geometry I think. 3. The attempt at a solution I definitely thought E would point up since the rod at the bottom has extra length that has positive charge, which would affect electric field to the radially outward direction. But the answer is b, E points down. Could anyone explain the reason? Thanks in advance.