  In the framework of the first Born approximation, we present a
semirelativistic theoretical study of the inelastic excitation
($1s_{1/2}\longrightarrow 2s_{1/2}$) of hydrogen atom by electronic impact. The
incident and scattered electrons are described by a free Dirac spinor and the
hydrogen atom target is described by the Darwin wave function. Relativistic and
spin effects are examined in the relativistic regime. A detailed study has been
devoted to the nonrelativistic regime as well as the moderate relativistic
regime. Some aspects of this dependence as well as the dynamic behavior of the
DCS in the relativistic regime have been addressed.
