Is the induced charge on the surface of a metal or inside it?

Two charged conducting spheres $S_1$ and $S_2$ of radii $8 \text{ cm}$ and $18 \text{ cm}$ are connected to each other by a wire. After equilibrium is established,the ratio of electric fields on $S_1$ and $S_2$ spheres are $E_{S_1}$ and $E_{S_2}$ respectively. The value of $\frac{E_{S_1}}{E_{S_2}}$ is . . . . . . .

Two charged spheres of radius $R_1$ and $R_2$ respectively are charged and joined by a wire. The ratio of the electric field at the surfaces of the spheres is . . . . . . .

$A$ and $B$ are two concentric conducting spherical shells. $A$ is given a positive charge $+Q$ while $B$ is earthed. Then:

$A$ hollow conducting sphere is placed in an electric field produced by a point charge placed at $P$ as shown in the figure. Let $V_A, V_B$,and $V_C$ be the potentials at points $A, B$,and $C$ respectively,where $A$ and $B$ are on the surface of the sphere and $C$ is inside the sphere. Then:

The figure shows a solid conducting sphere of radius $1 \, m$,enclosed by a metallic shell of radius $3 \, m$ such that their centers coincide. If the outer shell is given a charge of $6 \, \mu C$ and the inner sphere is earthed,find the charge on the surface of the inner sphere in $\mu C$.