Question

Three uncharged capacitors, $C_1,C_2$ and $C_3$ are connected to one another as shown in figure. The potential at point $\text{O}$ will be -

• A. $3\text{V}$
• B. $\frac{49}{11}\text{V}$
  
• C. $4\text{V}$
• D. $\frac{3}{11}\text{V}$

Answer 1

The correct option is B $\frac{49}{11}\text{V}$


In the figure, let us consider the potential at point $\text{O}$ is $V$.


Applying $\text{KCL}$ at junction $\text{O}$, we have,

$q_1+q_2+q_3=0$

$\Rightarrow 60(V-6)+20(V-2)+30(V-3)=0$

$\Rightarrow 60V-360+20V-40+30V-90=0$

$\Rightarrow 110V-490=0$

$\Rightarrow V=\frac{49}{11}\text{V}$

Hence, option $\left(B\right)$ is the correct answer.

Why this question? This question is aimed to recall the application of $\text{KCL}$ in a part of circuit consisting of capacitors.