Question

The given circuit shows an arrangement of four capacitors. A potential difference $30V$ is applied across the combination. It is observed that potentials at points $A$ and $B$ differ by $5V$. Also if a conducting wire is connected between $A$ and $B$, electrons will flow from $A$ to $B$. Of course, we have not actually connected a wire between $A$ and $B$, we have described only and 'if' situation. Potential difference across $C_4$ is :

• A. $12.5V$
• B. $15.5V$
• C. $17.5V$
• D. $22.5V$

Answer 1

The correct option is C $17.5V$

It is given that if we connect A and B by a wire, then electron will flow from A to B that means B is at higher potential than A
$V_B-V_A=5V$
If $C_1$ is at x potential difference then potential at point A will be $V_A=30-xV$
and point B will be at $V_B=30-(30-x)=xV$
Now $V_B-V_A=5V$
$x-(30-x)=5V$
$x=17.5V$
Potential difference across $C_4=17.5V$