An electron of mass $\mathrm{m}$ with an initial velocity $\overrightarrow{\mathbf{V}}=\mathbf{V}_{0} \hat{\hat{i}}\left(\mathrm{~V}_{0}>0\right)$ enters an electric field $\vec{E}=-E_{0} \hat{i}\left(E_{0}=\right.$ constant $>0$ ) at $t=0$. If $\lambda_{0}$ is its de-Broglie wavelength initially, then its de-Broglie wavelength at time $t$ is(1) $\lambda_{0} t$(2) $\lambda_{0}\left(1+\frac{\mathrm{e} \mathrm{E}_{0}}{\mathrm{mV}_{0}} \mathrm{t}\right)$(3) $\frac{\lambda_{0}}{\left(1+\frac{\mathrm{eE}_{0}}{\mathrm{mV}_{0}} \mathrm{t}\right)}$(4) $\lambda_{0}$