Question

Potential difference between $A$ and $B$ in the following circuit

• A. 4 V
• B. 5.6 V
• C. 2.8 V
• D. 6 V

Answer 1

Answer: (B)

Apply Kirchhoff's second loop law, go from $A$ to $B$ anti-clockwise
$I(2+8) =6-4 $
$I \cdot 10 =2 $
$I =0.2 A$
$V_{A}-I \times 2+6 =V_{B} $
$V_{A}-V_{B} =0 \cdot 2 \times 2-6 $
$=0.4-6=-5.6 \,V$
Hence, $V_{A} < V_{B}$
and $V_{B A}=5.6 \,V$