Three identical capacitors C1 C2 and C3 have a capacitance of 1.0μF 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 ∈r. 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 charge on C3 is found to be 5μC. The value of ∈r.