A thin spherical shell with radius R$1$R$1=4\mathrm{.}00$ cmcm is concentric with a larger thin spherical shell with radius R$2$R$2=8\mathrm{.}00$ cmcm$.$ Both shells are made of insulating material. The smaller shell has charge q$1=+6\mathrm{.}00$nCq$1=+6\mathrm{.}00$nC distributed uniformly over its surface, and the larger shell has charge q$2=9\mathrm{.}00$nCq$2=9\mathrm{.}00$nC distributed uniformly over its surface. Take the electric potential to be zero at an infinite distance from both shells.