The figure shows, in cross section, two solid spheres with uniformly distributed charge throughout their volumes. Each has radius $R.$ Point Plies on a line connecting the centers of the spheres, at radial distance $\frac{R^{}}{5}$ from the center of sphere $1.$ If the net electric field at point $P$ is zero, what is the ratio $\frac{q_2}{q_1}$ of the total charge $q_2$ in sphere $2$ to the total charge $q_1$ in sphere $1?$