JEE PYQ: Capacitance Question 22
Question 22 - 2020 (08 Jan Shift 1)
Effective capacitance of parallel combination of two capacitors $C_1$ and $C_2$ is 10 $\mu$F. When these capacitors are individually connected to a voltage source of 1 V, the energy stored in the capacitor $C_2$ is 4 times that of $C_1$. If these capacitors are connected in series, their effective capacitance will be:
(1) 4.2 $\mu$F
(2) 3.2 $\mu$F
(3) 1.6 $\mu$F
(4) 8.4 $\mu$F
Show Answer
Answer: (3)
Solution
In parallel: $C_1 + C_2 = 10,\mu$F. $\frac{U_2}{U_1} = \frac{C_2}{C_1} = 4$. So $C_2 = 8,\mu$F and $C_1 = 2,\mu$F. In series: $C_{eq} = \frac{C_1 C_2}{C_1 + C_2} = \frac{2 \times 8}{10} = 1.6,\mu$F.
BETA
