A combination of capacitors given is charged by a cell of emf E as shown :
If it is given that `V_(ab)` i.e. potential difference between points a and b is 4V, then answer the given questions.
Potential difference between points a and c will be:

Options

A. 4 V
B. 12 V
C. 10 V
D. 8 V

Answer

B

Explanation

Considering branch ac,
`V_(ab)=4V` (given)

`implies Q_(ab)=C_(ab)V_(ab)=12muFxx4V=48muC`
As, `12muC and 6muF` capacitors are in series.
`therefore`Charge on both must be same `implies Q_(bc)=48muC`
As, `C_(bc)=6muF,V_(bc)=(48)/(6)V=8V` hence, `V_(ac)=V_(a)-V_(c)=V_(a)-V_(b)+V_(b)-V_(c)=4+8=12V`.