Question

Find the potential difference between the points $A$ and $B$ and between the points $B$ and $C$ of figure in steady state.

• A. $20V$
• B. $25V$
• C. $75V$
• D. $100V$

Answer 1

Answer: (C)

Consider the problem

$\begin{array}{c}{c}_{eq}=\left[\left(3\mu fp3\mu f\right)s\left(1\mu fp1\mu f\right)\right]p\left(1\mu f\right)\\ =\left[\left(3+3\right)\mu fs\left(2\mu f\right)\right]p1\mu f\\ =\frac{3}{2}+1=\frac{5}{2}\mu f\end{array}$

$\begin{array}{c}v=100v\\ Q=cv=\frac{5}{2}\times 100=250\mu c\end{array}$

Charge stored across $1\mu f$ capacitor $=100\mu c$

$c_{eq}$ between $A$ and $B$ is $6\mu f=c$

Potential drop across $AB=v=\frac{Q}{c}=25v$

Potential drop across $BC=75v$

Hence,Option $C$ is the correct answer.