Three capacitors of capacitances `4muF,6muF` and `12 muF` are connected in series with a `110V` battery. The battery is disconnected,the three positive plates are connected together and the three negative plates are connected together. Find the charges on the three capacitors arter the reconnection.

Explanation

Before:
The equivalent capacitance
`(1)/(C_(eq))=(1)/(C_(1))+(1)/(C_(2))+(1)/(C_(3))=(1)/(4)+(1)/(6)+(1)/(12)=(3+2+1)/(12)=(1)/(2)`
`C_(eq)=2 muF`
In series, charge on each capacitor is same
`Q_(1)=Q_(2)=Q_(3)=C_(eq)V=2xx100=220 muC`
After reconnection:
Common potential:
`V=(Q_(1)+Q_(2)+Q_(3))/(C_(1)+C_(2)+C_(3))=(3xx220)/(4+6+12)=30V`
Final charges on capacitors:
`Q'_(1)=C_(1)V=4xx30=120 muC`
`Q'_(1)=C_(2)V=6xx30=180 muC`
`Q'_(1)=C_(3)V=12xx30=360 muC`