Question

In the given circuit potential of junction $P$ is :

• A. 4 V
• B. 0 V
• C. 3.2 V
• D. 2.8 V

Answer 1

The correct option is C 3.2 V



Let the voltage of point $P$ be $V_P$ and currents are flowing in the circuit as shown in the figure.

Here we assume that potential of point $P$ is higher than $2\text{V}$.

Now applying KVL between points of potential $12\text{V}$ and $2\text{V}$ :
$12-4i-2i_1=2$
$2i+i_1=5$ ------$\left(1\right)$

Applying KVL between points of potential $12\text{V}$ and $0\text{V}$ :
$12-4i-2(i-i_1)=0$
$3i-i_1=6$ ------$\left(2\right)$

From $\left(1\right)$ and $\left(2\right)$ we have,
$i=\frac{11}{5}\text{A}$

So, potential at point $P$,
$V_P=12-4i=12-4\times \frac{11}{5}=3.2\text{V}$