For an electron having a de Broglie wavelength of 0.167 nm (appropriate for interacting with crystal lattice structures that are about this size):

(a) Calculate the electron’s velocity, assuming it is nonrelativistic. 

(b) Calculate the electron’s kinetic energy in eV.

Strategy

For part (a), since the de Broglie wavelength is given, the electron's velocity can be obtained from  = h/p by using the nonrelativistic formula for momentum, p = mv. For part (b), once v is obtained (and it has been verified that v is nonrelativistic), the classical kinetic energy is simply (1/2)mv².