$A$ proton is $1840$ times heavier than an electron. When it is accelerated through a potential difference of $1 \ kV$,its kinetic energy is .......... $keV$.

$A$ Van de Graaff generator has a spherical metal shell as an electrode which is at a potential $15 \times 10^6 \,V$. If the dielectric strength of the surrounding medium is $5 \times 10^7 \,V/m$, then the diameter of the shell is (in $\,cm$)

Two point charges $-q$ and $+q$ are located at points $(0,0,-a)$ and $(0,0, a)$ respectively. The electric potential at a point $(0,0, z)$,where $z>a$ is

Three charged particles having charges $q, -2q$,and $q$ are placed in a line at points $(-a, 0), (0, 0)$,and $(a, 0)$ respectively. The expression for electric potential at $P(r, 0)$ for $r \gg a$ is ...............

Along the $X$-axis,three charges $\frac{q}{2}, -q$ and $\frac{q}{2}$ are placed at $x=0, x=a$ and $x=2a$ respectively. The resultant electric potential at $x=a+r$ (if $a << r$) is: ($\varepsilon_0$ is the permittivity of free space)

Two points $P$ and $Q$ are at potentials of $10 \ V$ and $-4 \ V$ respectively. The work done in moving $100$ electrons from $P$ to $Q$ is .....