Positive charge Q is distributed uniformly along the x axis from x = 0 to x = a.
(a) Determine the magnitude of the electric field at x = l + a on the x axis.
(b) Find an expression for the field if l≫a.

Two charged particles, q1 and q2, are located on the x-axis, with q1 at the origin and q2 initially at x1 = 12.2 mm. in this configuration, q1 exerts a repulsive force of 2.62 µn on q2. particle q2 is then moved to x2 = 18.0 mm. what is the force (magnitude and direction) that q2 exerts on q1 at this new location? (give the magnitude in µn.)