CaseI:(Airbetweenplates)Capacitance,C=E0AdCaseII:(Metalplateisinsertedbetweentheplates)capacitane,C′=E0Ad−t+tkWheret=thicknessofmetalplate=d2k=Dielectricconstantofmetalplate=∞]C′′=E0Ad−t+d2∞=E0Ad2=2E0Ad=2CHence,itcanbeconculedthatthenewcapacitancebecomesdoublethatofinitialcapacitane.