Charge q is divided in two parts q1 and q2 and these are placed at a distance r. For maximum repulsion between these parts
q1=q2=q/2
q1=3q/4 and q2=q/4
q1=2q/3 and q2=q/3
q1=(q−q/r) and q2=q/r
Here one charge is q1 then q2=q−q1Force between these two charges is given by F=14πε0×q1q−q1r2For maximum repulsion dFdq1=0=14πε0×q−2q1r2or q−2q1=0 or q1=q/2 and q2=q/2.