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 `4muF` capacitor will be

Options

A. `600 muC, 150` volts
B. `300 muC, 75` volts
C. `800 muC, 200` volts
D. `580 muC, 145` volts

Answer

D

Explanation

Total capacitance `(1)/(C ) = (1)/(20) + (1)/(8) + (1)/(12) rArr C = (120)/(31) muF`
Total charge `Q = CV = (120)/(31) xx 300 = 1161 muF`
Charge, through `4 muF` condenser `= (1161)/(2) = 580 muC`
and potential difference across it `= (580)/(4) = 145 V`