Question

A battery of emf. $10V$ is connected to resistance as shown in figure. The potential $V_A$ - $V_B$ difference between the points $A$ and $B$ is___

• A. $-2V$
• B. $2V$
• C. $5V$
• D. $\frac{20}{11}V$

Answer 1

Answer: (B)

$2V$

First we'll find the current in circuit from equivalent resistance of circuit

In upper and lower branch $1\Omega$ and $3\Omega$ are in series, their equivalent is $4\Omega$.

Now both $4\Omega$ resistances are in parallel, theirequivalent is $2\Omega$.

$2\Omega$ and $3\Omega$ are in series their equivalent is$5\Omega$.

$I=\frac{10}{5}=2A$

current will be equally divided between both branches, current in each branch will be $\frac{2}{2}=1A$

potential drop across $1\Omega$ is $1\times 1=1$ V

potential drop across $3\Omega$ is $1\times 3=3$ V

potential difference between between A and B is $3-1=2$ V

hence correct answer is option B.