Answer
$13.7\frac{Km}{s}$
Work Step by Step
According to De-Broglie hypothesis
$\lambda=\frac{h}{p}=\frac{h}{mv}$
$\implies v=\frac{h}{\lambda}$
We plug in the known values to obtain:
$v=\frac{6.63\times 10^{-34}}{6.69\times 10^{-27}\times 7.22\times 10^{-12}}$
$v=1.37\times 10^4\frac{m}{s}=13.7\frac{Km}{s}$
