A capacitor has air as dielectric medium and two conducting plates of area 12 cm^2 and they are 0.6 cm apart. When a slab of dielectric having area…

A capacitor has air as dielectric medium and two conducting plates of area $\displaystyle 12 \mathrm{~cm}^2$ and they are $\displaystyle 0.6$ cm apart. When a slab of dielectric having area $\displaystyle 12 \mathrm{~cm}^2$ and $\displaystyle 0.6$ cm thickness is inserted between the plates, one of the conducting plates has to be moved by $\displaystyle 0.2$ cm to keep the capacitance same as in previous case. The dielectric constant of the slab is : (Given $\displaystyle \epsilon_0=8.834 \times 10^{-12} \mathrm{~F} / \mathrm{m}$ )