question_answer

The potential difference between points A and B is:

A)  \[\frac{20}{7}V\]

B)  \[\frac{40}{7}V\]

C)  \[\frac{10}{7}V\]           

D)  zero

Correct Answer: D

Solution :

 From the given figure, current through lower branch of resistances which are joined in series is \[{{i}_{1}}=\frac{10}{4+32}=\frac{10}{7}A\] Again, current through upper branch of resistances which are also connected in series, is \[{{i}_{2}}=\frac{10}{8+6}=\frac{10}{14}A\] Now, according to the Kirchhoffs voltage law \[{{V}_{B}}-{{V}_{A}}=8\times {{i}_{2}}-4\times {{i}_{1}}\] \[=8\times \frac{10}{14}-4\times \frac{10}{7}=0\]