In the circuit shown in figure
Find the potential differnece across capacitor.

Explanation

When capacitor is fully charged, it fraws no currnet, and hence provides infinite resistance, then no current flows in arm EF. The potential difference across C and F. The resistance of arm AD and they together are in series with resistance of arm DF. The effective resistance between A and F of circuit is,
`R = (3xx6/3+6) + 3 = 2 +3 =5 Omega`
Main in the circuit, `i = 15/5=3 A`
Current through arm BCD
` = 1 xx 3/6+3 = 3xx3/9 = 1 A`
Potential difference across C and D `= 1 xx 3 = 3V`
Current through arm DF, i =3A
Potential differences across D and F `= 3 xx 3 = 9 V`
So, potential difference across C and F `= 3+ 9=12 V`
Thus, potential difference across the capacitor is 12 V