A beam of electrons, each with the same kinetic energy, illuminates a pair of slits separated by a distance of 52 nm. The beam forms bright and dark fringes on a screen located a distance 2.3 m beyond the two slits. The arrangement is otherwise identical to that used in the optical two-slit interference experiment. The bright fringes are found to be separated by a distance of 0.1 mm. Planck's constant is 6.63 × 10 -34 J · s. What is the kinetic energy of the electrons in the beam? Answer in units of keV.