Question

In the circuit shown, if a conducting wire is connected between points A and B, the current in this wire will:

• A. flow from A to B
• B. flow in the direction which will be decided by the value of V
• C. be zero
• D. flow from B to A

Answer 1

Answer: (D)

flow from B to A

Answer 2

As the bridge is not balance so the current will through wire.
The current through arm PAQ is $I_1=\frac {V}{(4+4)}=\frac V8$
The current through arm PBQ is $I_2=\frac {V}{(1+3)}=\frac V4$
Thus, $V_A−V_Q=4I_1$
$V_A−0=4(\frac V8)$ (as Q is connected in ground )
$V_A=\frac V2$
$V_B−V_Q=3I_2$
$V_B−0=3(\frac V4)$ (as Q is connected in ground )
$V_B=\frac {3V}{4}$
Since $V_B>V_A$, so current flow from B to A.

Therefore, the correct option is (D): flow from B to A