For a parallel plate capacitor (with vacuum between the
plates),
C = 
0
dA
ε
where A is the area of each plate and d the separation between them 10 If the medium between the plates of a capacitor is filled with an insulating
substance (dielectric), the electric field due to the charged plates induces
a net dipole moment in the dielectric This effect, called polarisation,
gives rise to a field in the opposite direction