11. The figure shows a uniformly charged rod of total charge Q and total length L. Point P lies on the perpendicular bisector at distance D. Which of the following expressions best gives the magnitude of the electric field at P?
(A)
(B)
(C)
(D)
(E) 
11. The figure shows a uniformly charged rod of total charge Q and total length L. Point P lies on the perpendicular bisector at distance D. Which of the following expressions best gives the magnitude of the electric field at P?
(A)
(B)
(C)
(D)
(E) 