  We study the nucleon electromagnetic (EM) form factors in symmetric nuclear
matter as well as in vacuum within a light-front approach using the in-medium
inputs calculated by the quark-meson coupling model. The same in-medium quark
properties are used as those used for the study of in-medium pion properties.
The zero of the proton EM form factor ratio in vacuum, the electric to magnetic
form factor ratio $\mu_p G_{Ep}(Q^2)/G_{Mp}(Q^2)$ ($Q^2 = -q^2 > 0$ with $q$
being the four-momentum transfer), is determined including the latest
experimental data by implementing a hard constituent quark component in the
nucleon wave function. A reasonable fit is achieved for the ratio
$\mu_pG_{Ep}(Q^2)/G_{Mp}(Q^2)$ in vacuum, and we predict that the $Q_0^2$ value
to cross the zero of the ratio to be about 15 GeV$^2$. In addition the double
ratio data of the proton EM form factors in $^4$He and H nuclei, $[G^{^4{\rm
He}}_{Ep}(Q^2)/G^{^4{\rm He}}_{Mp}(Q^2)]/[G^{^1{\rm H}}_{Ep}(Q^2)/G^{^1{\rm
H}}_{Mp}(Q^2)]$, extracted by the polarized ($\vec{e}, e' \vec{p}$) scattering
experiment on $^4$He at JLab, are well described. We also predict that the
$Q_0^2$ value satisfying $\mu_pG_{Ep}(Q_0^2)/G_{Mp}(Q_0^2) = 0$ in symmetric
nuclear matter, shifts to a smaller value as increasing nuclear matter density,
which reflects the facts that the faster falloff of $G_{Ep}(Q^2)$ as increasing
$Q^2$ and the increase of the proton mean-square charge radius. Furthermore, we
calculate the neutron EM form factor double ratio in symmetric nuclear matter
for $0.1 < Q^2 < 1.0$ GeV$^2$. The result shows that the neutron double ratio
is enhanced relative to that in vacuum, while for the proton it is quenched,
and agrees with an existing theoretical prediction.
