Question

In the figure, three capacitors each of $6\text{pF}$ are connected in series. The equivalent capacitance of the combination is

• A. $9\text{pF}$
• B. $6\text{pF}$
• C. $3\text{pF}$
• D. $2\text{pF}$

Answer 1

The correct option is D $2\text{pF}$

In series combination, the equivalent capacitance is given by

$\frac{1}{C_{eq}}=\frac{1}{C_1}+\frac{1}{C_2}+\frac{1}{C_3}$

$\Rightarrow \frac{1}{C_{eq}}=\frac{1}{6}+\frac{1}{6}+\frac{1}{6}=\frac{1}{2}$

$\Rightarrow C_{eq}=2\text{pF}$

Hence, option $\left(d\right)$ is correct.

Key Concept: Effective capacitance in a series combination of capacitors in a circuit.