When air$-$filled, a particular parallel$-$plate capacitor has a capacitance of c$1=19\mathrm{.}7$Fc$1=19\mathrm{.}7$F$.$ When the gap between the plates is filled with a dielectric oil, the capacitance changes to c$2=35\mathrm{.}4$Fc$2=35\mathrm{.}4$F$.$ A potential difference of $12$V$12$V is applied.