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 \[{{i}_{1}}=\frac{10}{4+3}=\frac{10}{7}amp\] Again current through upper branch of resistances which are also connected in series, is \[{{i}_{2}}=\frac{10}{8+6}=\frac{10}{14}amp\] Now according to the Kirchhoff's voltage law \[{{V}_{B}}-{{V}_{A}}=8\times {{i}_{2}}-4\times {{i}_{1}}\] \[=8\times \frac{10}{14}-4\times \frac{10}{7}\] \[=0\]