question_answer

Four resistors are connected as shown in following figure. A 6V battery of negligible resistance is connected across terminals A and C. The potential difference across terminals B and D will be

A)  \[0\,V\]            

B) \[1.5\,V\]

C) \[3\,V\]             

D) \[2\,V\]

Correct Answer: A

Solution :

[a] Redrawing the given circuit \[I=\frac{6}{{{R}_{eq}}},\,{{R}_{eq}}=\frac{40}{3}\Omega \] \[I=\frac{9}{20}A\] \[{{I}_{(5,\,\,15)}}=\frac{3}{10}A;\] \[{{I}_{(10,30)}}=\frac{3}{20}A\] \[{{V}_{across\,\,15}}=15\times \frac{3}{10}=4.5V\] \[{{V}_{across\,\,30}}=30\times \frac{3}{20}=\frac{9}{2}=4.5V\] \[{{V}_{BD}}=0V\]