The $ \lambda$ of light from the spectral emission line of sodium is $589\: nm$. Find the $KE$ at which an electron would have the same de Broglie wavelength.

Question

$\begin {array} {1 1} (a)\;69 \times 10^{-26} J & \quad (b)\;4.31 \: neV \\ (c)\;3.78 \times 106{-28} J & \quad (d)\;2.36\: \mu\: eV \end {array}$