Inside a charged hollow sphere,at any point the electric field $(E)$ and potential $(V)$ are

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

What is earthing or grounding in household electrical circuits?

$A$ spherical conductor of radius $2 \, m$ is charged to a potential of $120 \, V$. It is now placed inside another hollow spherical conductor of radius $6 \, m$. Calculate the potential to which the bigger sphere would be raised. (in $, V$)

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 spherical conductors $A$ and $B$ of radii $R_1$ and $R_2$ are charged to the same potential and placed at a distance $d$ apart. If these spheres are connected by a conducting wire,what is the ratio of the magnitudes of the electric fields at the surfaces of $A$ and $B$ in the equilibrium state?