Question

The equivalent capacitance of the combination shown in the figure across the terminals $\text{PQ}$ below is

• A. $25$ $\mu \text{F}$
• B. $10$ $\mu \text{F}$
• C. $36$ $\mu \text{F}$
• D. $5$ $\mu \text{F}$

Answer 1

The correct option is B $10$ $\mu \text{F}$



Clearly, point $\text{a}$ and $\text{b}$ have same potential.

So, the potential drop across 6 $\mu \text{F}$ and $3\mu \text{F}$ capacitor is zero.

Also, point $\text{c}$ and $\text{d}$ have same potential.

So, the potential drop across $12\mu \text{F}$ capacitor is also zero.

The circuit reduces to


$\Rightarrow C_{eq}=10\mu \text{F}$

Why this Question ? To properly apply the technique of successive reduction, always concentrate on equipotential points in a circuit. Then, look for the possible series and parallel combinations to further simplify the circuit.