Question

A capacitor is composed of two plates separated by 3 mm dielectric of relative permittivity 4. An additional piece of insulation 5 mm thick is now inserted between the plates. If the capacitor has now capacitance one-third of its original capacitance, find the relative permittivity of the additional dielectric.

Answer 1

 Fig. 5.40 (i) and Fig. 5.40 (ii) respectively show the two cases.