The electric potential at the surface of a hollow metallic sphere is $10\, V$. What will be the electric potential at its center (in $, V$)?

Two identical metal balls of radius $r$ are at a distance $a$ $(a \gg r)$ from each other and are charged,one with potential $V_1$ and other with potential $V_2$. The charges $q_1$ and $q_2$ on these balls in $CGS$ $esu$ are

Two conducting spheres of radii $9 \,cm$ and $1 \,cm$ are separated by a distance of $20 \,cm$ in free space. If the spheres are charged to the same potential of $10 \,V$ each, the force of repulsion between them is

The electric potential at a distance of $R/2$ from the center of a charged conducting sphere of radius $R$ is .......

Two point charges $q_1$ and $q_2$ are separated by a distance $d$. What is the increase in potential energy of the system when $q_2$ is moved towards $q_1$ by a distance $x$? $(x < d)$ (where $\frac{1}{4 \pi \varepsilon_0} = K$ is a constant).

Particles $A$ and $B$ have charges $+q$ and $+4q$ respectively. Both have the same mass $m$. If they are released from rest and accelerated through the same potential difference $V$,the ratio of their velocities $v_A/v_B$ is: