# Two positively charged particles , each of mass $\;1.7\times10^{-27}\;kg\;$ are carrying a charge of $\;1.6\times10^{-19}\;$ are placed r distance apart. If each one experiences a repulsive force equal to its weight , find r ?

$(a)\;0.117\;m\qquad(b)\;0.011\;m\qquad(c)\;1.17\;m\qquad(d)\;1.17\;cm$

Answer : (a) $\;0.117\;m$
Explanation : $\; F=\large\frac{Rq^2}{r^2}=mg$
$=\large\frac{9\times10^{9}\times(1.6\times10^{-19})^2}{r^2}=1.7\times10^{-27}\times10$
$r=1.17\times10^{-1}\;m\;.$