In the circuit shown in the figure four capacitors are connected to a battery. The `p.d` across the `7 mu F` capacitor is `6V`.
.

Options

A. The p.d across the `12 mu F` capacitor is `10 V`
B. The charge on the `3 mu F` capacitor is `42 mu C`
C. The p.d across `3.9 mu F` capacitor is `10 V`
D. The emf of the battery is `30 V`

Answer

A, B, D

Explanation

`q-[3.9 +(7 xx3)/(7+3)] xx[6+(7 xx6)/(3)]=120 muC`
p.d across `12 muF` capacitor `= (120)/(12)=10 V(A)`
Charge on `3 mu F` capacitor `= 7 xx 6 =42 muC (B)` p.d across
`3.9 mu F` capacitor `= 6+((7xx6)/(3))=20 V`
The emf of the battery `=20+10=30 V(D)`.