Abeam 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 1.8 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 1 mm. what is the kinetic energy of the electrons in the beam? planck’s constant is 6.63 × 10−34 j · s. answer in units of kev.