Question

Three capacitors each of capacitance $1\mu F$ are connected in parallel. To this combination, a fourth capacitor of capacitance $1\mu F$ is connected in series. The resultant capacity of the system is :

• A. All three capacitors are connected in parallel
• B. All three capacitors are connected in series
• C. Third capacitor is in series with a parallel combination of the other two
• D. Third capacitor is in parallel with a series combination of the other two

Answer 1

Answer: (A), (D)

Third capacitor is in parallel with a series combination of the other two
All three capacitors are connected in parallel

For parallel,
$C_1=C_{eff}=1+1+1=3$
Now for series,
$\therefore \frac{1}{C_{eff}}=\frac{1}{C_1}+\frac{1}{C_2}=\frac{1}{3}+1=\frac{4}{3}$
$\therefore C_{eff}=\frac{3}{4}\mu F$