Question

In the figure, a potential of $+1200V$ is given to point $A$ and point $B$ is earthed. What is the potential at the point $P$ ?

• A. 100 V
• B. 200 V
• C. 400 V
• D. 600 V

Answer 1

Answer: (C)

Given circuit can be reduced as follows

In series combination, charge on each capacitor remains same.
So using $Q=CV$
$\Rightarrow C_1{V}_1=C_2{V}_2$
$\Rightarrow 3\left(1200-V_p\right)=6\left(V_P-V_B\right)$
$\Rightarrow 1200-V_p=2V_p$
$\left(\because V_B=0\right)$
$\Rightarrow 3V_p=1200$
$\Rightarrow V_p=400$ volt