question_answer

In the electric network shown, when no current flows through the \[4\Omega \]resistor in the arm EB, the potential difference between the points A and D will be :                           [JEE MAIN 11-04-2015]

A) 3V

B) 4V

C) 5V

D) 6V

Correct Answer: C

Solution :

[c]

If current in \[4\Omega \] is zero then \[\underset{BCDE}{\mathop{{{\varepsilon }_{v}}}}\,=0\]

\[{{V}_{EB}}+{{V}_{BC}}+{{V}_{CD}}+{{V}_{DE}}=0\]

\[-4+3+{{V}_{CD}}+0=0\]

\[{{V}_{CD}}=1\]volt

again \[{{V}_{A}}-9+3+1-{{V}_{D}}=0\]

\[{{V}_{A}}-{{V}_{D}}=5V\]EXAM