An electron of mass m is moving in an electric field E =-2 E_o i (E_o =. constant.>0), with an initial velocity V =v_o i (v_o =. constant.>0). If λ_o…

An electron of mass $\displaystyle m$ is moving in an electric field $\displaystyle \vec{E}=-2 E_{\mathrm{o}} \hat{i}\left(E_{\mathrm{o}}=\right.$ constant $\displaystyle \left.>0\right)$, with an initial velocity $\displaystyle \vec{V}=v_{\mathrm{o}} \hat{i}$ $\displaystyle \left(v_{\mathrm{o}}=\right.$ constant $\displaystyle \left.>0\right)$. If $\displaystyle \lambda_{\mathrm{o}}=\frac{h}{4 m v_{\mathrm{o}}}$, its de Broglie wavelength at time $\displaystyle t$ is $\displaystyle \_\_\_\_$. ( $\displaystyle e=$ charge of electron)