Question

In the circuit shown, the cell has an emf of $10V$ and internal resistance of $1ohm$, the other resistance are shown in the figure. The potential difference $V_A-V_B$ is

• A. $6V$
• B. $4V$
• C. $2V$
• D. $-2V$

Answer 1

Answer: (D)

$-2V$

Equivalent external resistance of the given circuit $R_{eq}=4\Omega$

Current given by the cell $i=\frac{E}{R_{eq}+r}=\frac{10}{(4+1)}=2A$

Hence, $(V_A-V_B)=\frac{i}{2}\times (R_2-R_1)=\frac{2}{2}(2-4)=-2V$