An electron of mass m with an initial velocity V = V_0 i ( V_0>0) enters an electric field E =- E_0 i ( E_0=. constant.>0) at t =0. If λ_0 is its…

An electron of mass $\displaystyle m$ with an initial velocity $\displaystyle \overrightarrow{\mathrm{V}}=\mathrm{V}_0 \hat{\mathrm{i}}\left(\mathrm{V}_0>0\right)$ enters an electric field $\displaystyle \overrightarrow{\mathrm{E}}=-\mathrm{E}_0 \hat{\mathrm{i}}\left(\mathrm{E}_0=\right.$ constant $\displaystyle \left.>0\right)$ at $\displaystyle \mathrm{t}=0$. If $\displaystyle \lambda_0$ is its de-Broglie wavelength initially, then its de-Broglie wavelength at time t is