Condsider
.
In the circuit shown is the switch can be shifted to positions `1` and `2` The charge on capacitor `C_(1)` when the switch is at position `1` is.

Options

A. `120 muC`
B. `240 muC`
C. `360 muC`
D. `80 muC`

Answer

C

Explanation

When switch is in position `1`,
`30=q/(20)-q/(30)=0` or `q=360 muC`
Now, the switch is in position`2`,
.
Loop` ABCD`,

`(Q'_(1))/(20)-(Q'_(1))/(30)+Q_(3)/(20)=0`
or `-3q'_(1)-2q_(1)+3q_(3)=0`
or `5q'_(1)=3q_(3)` or `q'_(1)=(3)/(5)q_(3)`
`(8q_(3))/5=360`
`q_(3)=(360xx5)/8=(450)/2muC=225muC` (ii)
`q'_(1)=3/5((450)/(2))=135 muC`.