Question

A parallel plate air capacitor has a capacitance of 5 F. What is the capacitance if a dielectric of relative permeability of 2 is inserted between the plates of the original air capacitor?

Answer 1

The capacitance of parallel plate capacitor

$$C=\frac{\kappa \epsilon_0A}{d}=\kappa C_0\\ =\rm 2\times 5\: F=10\: F$$