The electrostatic potential on the surface of a charged conducting sphere is $100 \mathrm{V}$. Two statements are made in this regard
$S_1:$ at any point inside the sphere, the electric field intensity is zero.
$S_2:$ at any point inside the sphere, the electrostatic potential is $100 \mathrm{V}$.

Which of the following is a correct statement?

There exists a uniform electric field in the space as shown. Four points $A$, $B$, $C$ and $D$ are marked which are equidistant from the origin. If $V_{\mathrm{A}}$, $V_{\mathrm{B}}$, $V_{\mathrm{C}}$ and $V_{\mathrm{D}}$ are their potentials respectively, then

Four similar charges each of charge $+q$ are placed at the four corners of a square of side $a$. Find the value of the integral $-{\int }_{\infty }^{a/\sqrt{2}}\overrightarrow{E}·\overrightarrow{dr}$ (in $\mathrm{Volts}$) if the value of  the integral,

$-{\int }_{a/\sqrt{2}}^0\overrightarrow{E}·\overrightarrow{dr}=\frac{\sqrt{2}Kq}{a}$ (where $K=\frac{1}{4\pi {\epsilon }_0}$)