Determine the de Broglie wavelength of:

A$.$ An electron with kinetic energy of $1\mathrm{.}2$ eV

B$.$ An alpha particle, also with kinetic energy $1\mathrm{.}2$ eV$.($An alpha particle is a helium nucleus with two protons and two neutrons. It has mass of $6\mathrm{.}644$x$10$²⁷ kg$).$