Question

Three capacitors of capacitances `5muF,2muF` and `2muF` are charged to 20 V, 30 V and 10 V respectively and then connected in the circuit with polarities as shown. The magnitude of charge flown through the battery after closing the switch S is
A. `25muC`
B. `40muC`
C. `50muC`
D. `75muC`

Answer 1

Correct Answer - A

`(q)/(5)+((q-40)/(2))+((q-120)/(2))=10`
`(6q)/(5)=90`
`q=75muC`
`therefore` magnitude of charge flown through the battery is
`Deltaq=100-75=25muC`