f=kq1q2/r2
r=корень(kq1q2/f)=
=корень(9*10(9)нм2/кл2*1.3*10(-9)кл*1.3*10(-9)кл/1.69*10(-5)н)=
=корень(9*10(-4))=3*10(-2)м=0.03м=3см