Question

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

• A. $5V$
• B. $3V$
• C. $6V$
• D. $4V$

Answer 1

Answer: (A)

Let the potential of point $B=0$
$\therefore$ Potential of point A and C will be $9V$ and $3V$ respectively.
By applying KCL at E
$I_1+I_3=I_2$
as $I_3=0\therefore I_1=I_2$
Also as $I_3=0$
$V_E=V_B+4=4volts$
$V_E=V_D=4volts$
$\therefore$ Potential difference between point A and D will be
$=V_A-V_D$
$=(9-4)volts$
$=5volts=5V$
(Thus option A)