Electrostatics

An electron moving with velocity \(1.6 \times 10^7 \mathrm{~m} / \mathrm{s}\) has wavelength of \(0.4 \mathop A\limits^o\). The required accelerating voltage for the electron motion is [charge on electron \(=1.6 \times 10^{-19} \mathrm{C}\), mass of electron \(=9 \times 10^{-31} \mathrm{~kg}\) ]