A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference $V$ esu. If $e$ and $m$ are charge and mass of an electron, respectively, then the value of $\large\frac{h}{\lambda}$ (where $\lambda$ is wavelength associated with electron wave) is given by

Question

$\begin{array}{1 1} (1) me\; V \\ (2)2me\; V\\ (3) \sqrt{me V} \\(4)\sqrt{2 me V}\end{array}$