Question

In the given circuit, the potential difference between A and B is 18 V and charge on 2 uF capacitor is 24 uc.
The value of C is
(1) 1 uF
(3) 3 uF
(2) 2 uF
(4) 4 uF​

Answer 1

For 2 uF, q = CV

24uC = 2uF. V

V = 12 V

For 6 uF, q = CV

q = 6uF. ( 18-12 )V

q = 36 uC

Q = Q'( 2uF) + Q"(C)

36 uC = 24uC + Q"(C)

Q" = 12uC

Q" = CV

12uC = C. 12V ( same voltage as of 2uF capacitor, due to parallel combination)

• C = 1uF

Option 1). 1uF is correct.