  The electromagnetic decay contributions to $J/\psi(\psi^\prime)\to VP$, where
$V$ and $P$ stand for vector and pseudoscalar meson, respectively, are
investigated in a vector meson dominance (VMD) model. We show that $J/\psi
(\psi^\prime)\to \gamma^*\to VP$ can be constrained well with the available
experimental information. We find that this process has significant
contributions in $\psi^\prime\to VP$ and may play a key role in understanding
the deviations from the so-called "12% rule" for the branching ratio fractions
between $\psi^\prime\to VP$ and $J/\psi\to VP$. We also address that the "12%
rule" becomes very empirical in exclusive hadronic decay channels.
