
A parallel plate capacitor has a dielectric slab of a dielectric constant between its plates that covers of the area of its plates, as shown in the figure. The total capacitance of the capacitor is while that of the portion with dielectric in between is . When the capacitor is charged, the plate area covered by the dielectric gets charge and the rest of the area gets charge . Choose the correct option/options, ignoring edge effects.




Important Questions on Capacitance
A parallel plate capacitor having plates of area and plate separation , has the capacitance in air. When two dielectrics of different relative permittivity are introduced between the two plates as shown in the figure, the capacitance becomes . The ratio is,

Three identical capacitors , and have a capacitance of each and they are uncharged initially. They are connected in a circuit as shown in the figure and is then filled completely with a dielectric material of relative permittivity . The cell electromotive force . First the switch is closed while the switch is kept open. When the capacitor is fully charged, is opened and is closed simultaneously. When all the capacitors reach equilibrium, the charge on is found to be . The value of






In the given circuit, the charge on the capacitor changes as is varied from to . as a function of is given properly by (figures are drawn schematically and are not to scale)
