Question

Two capacitors of capacitances $C_1$ and $C_2$ are connected across $200 \,V$ power supply. The potential drop across $C_1$ is $120\, V. A$ capacitor of capacitance $2\,\mu F$ is connected in parallel with $C_1$ and the potential drop across $C_2$ becomes $160\, V$. What are the values of $C_1$ and $C_2$ in $\mu F$ ?

• A. 0.4 and 0.6
• B. 0.6 and 0.4
• C. 0.8 and 1.2
• D. 1.2 and 0.8

Answer 1

Answer: (A)

0.4 and 0.6

Answer 2

Initially the charge is same on both capacitors. Therefore, 120 $C_1$ = 80 $C_2$. Afterwards $(C_1+2)$ 40 = 160 $C_2$. This gives $C_1 = 0.4 \, \mu$F and $C_2 = 0.6\, \mu$F.