Q is called the charge of the capacitor, though
this, in fact, is the charge on one of the conductors – the total charge  of
the capacitor  is zero The electric field in the region between the
conductors is proportional to the charge Q That
is, if the charge on the capacitor is, say  doubled,
the electric field will also be doubled at every point (This follows from the direct proportionality
between field and charge implied by Coulomb’s
law and the superposition principle