  Following recent studies of non-relativistic reductions of the single-nucleon
electromagnetic current operator, here we extend the treatment to include meson
exchange current operators. We focus on one-particle emission electronuclear
reactions. In contrast to the traditional scheme where approximations are made
for the transferred momentum, transferred energy and momenta of the
initial-state struck nucleons, we treat the problem exactly for the transferred
energy and momentum, thus obtaining new current operators which retain
important aspects of relativity not taken into account in the traditional
non-relativistic reductions. We calculate the matrix elements of our current
operators between the Fermi sphere and a particle-hole state for several
choices of kinematics. We present a comparison between our results using
approximate current operators and those obtained using the fully-relativistic
operators, as well as with results obtained using the traditional
non-relativistic current operators.
