Three identical capacitors C1 ,C2 and C3 have a capacitance of 1.0 μF each and they are uncharged initially. They are connected in a circuit as shown in the figure and C1 is then filled completely with a dielectric material of relative permittivity εr. The cell electromotive force (emf) V0=8V. First the switch S1 is closed while the switch S2 is kept open. When the capacitor C3 is fully charged, S1 is opened and S2 is closed simultaneously. When all the capacitors reach equilibrium, the acitors reach equilibrium, the charge on C3 is found to be 5μC . The value of εr= .......
