The potential difference between $\mathrm{A}$ and $\mathrm{B}$ in the following circuit is

• Correct answer
  A

  $\mathrm{4 }\mathrm{V}$
• B

  $\mathrm{5.6 }\mathrm{V}$
• C

  $\mathrm{2.8 }\mathrm{V}$
• D

  $\mathrm{6 }\mathrm{V}$

Solution

Applying Kirchhoff's voltage law, 

$I\left(2+8\right)=6+4$

$I.10=10$

$I=\mathrm{1 }\mathrm{A}$

$V_{\mathrm{A}}-\left(I\times 2\right)+6=V_B$

$V_A-V_B=\left(1\times 2\right)-6$

And $V_{BA}=\mathrm{4 }\mathrm{V}$

Hence, the correct answer is option: 'A'.