In the adjoining figure, four capacitors are shown with their respective capacities and the P.D. applied. The charge and the P.D. across the 4μF  capacitor will be.

Total capacitance  1C=120+18+112⇒C=12031μFTotal charge  Q=CV=12031×300=1161μCCharge, through 4μF condenser  =11612=580μCand potential difference across it  =5804=145 V.