An electron is moving with a kinetic energy of $4.55\times {10}^{-25}.$ What will be de Broglie wavelength for this electron ?

$\begin{array}{l}\mathrm{KE}=\frac{1}{2}{\mathrm{mv}}^2=4.55\times {10}^{-25}\\ {\mathrm{V}}^2=\frac{2\times 4.55\times {10}^{-25}}{9.1\times {10}^{-31}}=1\times {10}^6\\ \mathrm{V}={10}^3\mathrm{m}/\mathrm{s}\\ \mathrm{de}\mathrm{Broglie}\mathrm{wavelength}\mathrm{\lambda }=\frac{\mathrm{h}}{\mathrm{mv}}\\ =\frac{6.626\times {10}^{-34}}{9.1\times {10}^{-31}\times {10}^3}=7.28\times {10}^{-7}\mathrm{m}\\ \end{array}$