An electron (mass m) with an initial velocity $\overrightarrow{\mathrm{v}}={\mathrm{v}}_0\hat{\mathrm{i}}\left({\mathrm{v}}_0>0\right)$ is moving in an electric field $\overrightarrow{\mathrm{E}}=-{\mathrm{E}}_0\hat{\mathrm{i}}\left({\mathrm{E}}_0>0\right)$ where E₀ is constant. If at t = 0 de Broglie wavelength is ${\mathrm{\lambda }}_0=\frac{\mathrm{h}}{{\mathrm{mv}}_0}$, then its de Broglie wavelength after time t is given by