Dual Nature Of Radiation

The work done to accelerate an electron from rest so that it can have a de-Broglie wavelength of $6600 \mathop {\rm{A}}\limits^{\rm{o}}$ is nearly

(Planck's constant $=6.6 \times 10^{-34} \mathrm{Js}$ and mass of electron $=9 \times 10^{-31} \mathrm{~kg}$ )