Figure shows a positively charged infinite wire. $A$ particle of charge $2C$ moves from point $A$ to $B$ with constant speed. (Given linear charge density on wire is $\lambda = 4 \pi \varepsilon_0$)

Two equal charges $q$ are placed at a distance of $2a$ and a third charge $ – 2q$ is placed at the midpoint. The potential energy of the system is

A particle $A$ has charge $+q$ and particle $B$ has charge $+4 q$ with each of them having the same mass $m$. When allowed to fall from rest through the same electric potential difference, the ratio of their speeds $\frac{V_A}{V_B}$ will become

$n$ the rectangle, shown below, the two corners have charges ${q_1} = – 5\,\mu C$ and ${q_2} = + 2.0\,\mu C$. The work done in moving a charge $ + 3.0\,\mu C$ from $B$ to $A$ is………$J$ $(1/4\pi {\varepsilon _0} = {10^{10}}\,N{\rm{ – }}{m^2}/{C^2})$

An electron of mass $m$ and charge $e$ is accelerated from rest through a potential difference $V$ in vacuum. The final speed of the electron will be