Two rods AB and BC have charges +2Q and -2Q uniformly distributed on them. They are bent in the shape of arcs of a circle and joined at B.
1. Find the linear charge density on rod AB.
2. Find the electric field at the midpoint between A and C.
3. Now a small object of mass M and electric charge 3Q is placed at the mid point between A and C. If it is free to move, find the acceleration (magnitude and direction) of this small mass.