(21-64) Suppose both charges in Fig. 21-45 (for a dipole) were positive, (a) Show that the field on

(21-64) Suppose both charges in Fig. 21-45 (for a dipole) were positive, (a) Show that the field on the perpendicular bisector, for r≫l, is given by 1/4πε_02Q/r^2. (b) Explain why the field decreases as 1/r^2 here where as for a dipole it decreases as 1/r^3