Question

In the circuit shown, what is the potential difference $V_{PQ}$ between points $P$ and $Q$?

• A. $+3\text{V}$
• B. $+2\text{V}$
• C. $-2\text{V}$
• D. None

Answer 1

The correct option is B $+2\text{V}$

Using Kirchhoffs junction law, current in the circuit can be assumed as:


Using $KVL$ in loop ABQCA
$-5I_1+1+4=0$
$I_1=1A$

Using $KVL$ in loop APDCA

$-1(I-I_1)+2-2(I-I_1)+4=0$
$3(I-I_1)=6\Rightarrow 3I-3I_1=6$
$I=3A$


Now $KVL$ between points P and Q
$V_P=-2+2(I-I_1)+V_Q$
$V_P=-2+2\left(2\right)+V_Q$
$V_P-V_Q=2V$