$a=\frac{F}{m}=\frac{q E}{m}$
$a_{A}=\frac{1}{4} a_{B}$
Now $v^{2}=u^{2}+2 a x$
since, $x$ is the same for both the particles.
$\Rightarrow \quad v_{A}^{2}=0+2 a_{A} x$ and $v_{B}^{2}=0+2 a_{B} x$
$\Rightarrow \frac{v_{A}^{2}}{v_{B}^{2}}=\frac{a_{A}}{a_{B}}=\frac{1}{4} \Rightarrow \frac{v_{A}}{v_{B}}=\frac{1}{2}$


If a point charge $q_A$ is placed at the center of the shell, then choose the correct statement $(s)$