A spherical capacitor has an inner sphere of radius 12 cm and an outer sphere of radius 13 cm. The outer sphere is earthed and the inner sphere is given a charge of $2.5 \mu C$. The space between the concentric spheres is filled with a liquid of dielectric constant $32$. What is the potential of the inner sphere?

Question

$\begin{array}{1 1} 4.5 \times 10^{6}\;V \\ 4.5 \times 10^{2}\;V \\ 6.5 \times 10^{6}\;V \\ 5.5 \times 10^{6}\;V \end{array}$