Answer
$V=256$ keV
Work Step by Step
In the given scenario:
Kinetic energy=potential energy
Therefore;
$\frac{1}{2}mv^2=eV$
We plug in the known values to obtain:
$\frac{1}{2}\times 9.109\times 10^{-31}\times (3\times 8)^2=1.6\times 10^{-19}V$
$V=2.56190625\times 10^{25}=256$ keV
