1)

For the resistance network shown in the figure, choose the correct option(s)

24112021111_m6.PNG


A) The current through PQ is zero

B) $I_{1}=3A$

C) The potential at S is less than that at Q

D) $I_{2}=2A$

Answer:

Option (A,B,C,D)

Explanation:

Due to symmetry on upper side and lower side, points P and Q are at same potentials. Similarly, points S and T are at same potentials. Therefore, the simple circuit can be drawn as shown

6112021210_n2.PNG

   $I_{2}= \frac{12}{2+2+2}=2A$

 $I_{3}=\frac{12}{4+4+4}=1A$

 $\therefore$    $I_{1}=I_{2}+I_{3}=3A$

 $I_{PQ}=0$ because $V_{p}=V_{Q}$ Potential drop (from left to right) across each resistance is 

 $\frac{12}{3}=4V$

 $\therefore$    $V_{MS}=2 \times 4=8V$

     $V_{NQ}=1 \times 4=4V$

 or $V_{S} < V_{Q}$