A parallel$-$plate capacitor has capacitance $\backslash ($ C$=12\mathrm{.}5\backslash$mathrm$\{$pF$\}\backslash )$ when the volume between the plates is filled with air. The plates are circular, with radius $3\mathrm{.}00$ cm $.$ The capacitor is connected to a battery and a charge of magnitude $25\mathrm{.}0$ pC goes onto each plate. With the capacitor still connected to the battery, a slab of dielectric is inserted between the plates, completely filling the space between the plates. After the dielectric has been inserted the charge on each plate has magnitude $45\mathrm{.}0$ pC $.$

Part A

What is the dielectric constant $\backslash ($ K $\backslash )$ of the dielectric?

$\backslash (\backslash$checkmark $\backslash )$ Correct