Let a total charge 2 Q be distributed in a sphere of radius R, with the charge density given by ρ( r )= kr, where r is the distance from the centre.…

Let a total charge $\displaystyle 2$ Q be distributed in a sphere of radius R , with the charge density given by $\displaystyle \rho(\mathrm{r})=\mathrm{kr}$, where r is the distance from the centre. Two charges A and B, of -Q each, are placed on diametrically opposite points, at equal distance, a, from the centre. If A and B do not experience any force, then :