In Wheat stone’s bridge shown in the adjoining figure galvanometer gives no deflection on pressing the key, the balance condition for the bridge is :

At balance, the potentials of point B and D are same and there will be no current in the arm BD. Thus,i1R1=qC1...(1)where q is the charge on both the capacitor plates connected in series.Quite similarly VB−VC=VD−VCor i1R2=qC2...(2)Dividing eqs. (i) and (ii), we getR1R2=C2C1