Question

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

• 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)

Current will flow from higher to lower potential.

Before connecting wire from $A$ to $B$, voltage drop
across $4\Omega =V\times \frac{4}{4+4}=\frac{V}{2}$
Voltate drop across $1\Omega =V\times \frac{1}{1+3}=\frac{V}{4}$
$\therefore$ voltage drop at $A=V-\frac{V}{2}=\frac{V}{2}$
and volatage drop at $B=V-\frac{V}{4}=\frac{3V}{4}$
So, $V_B>V_A$
Hence, on connecting wire between points $A$ and $B$, the current will flow from $B$ to $A$.