question_answer

Seven resistors, each of value \[5\Omega \] are connected as shown in figure. The equivalent resistance between points A and B is

A)  \[5\Omega \]                   

B)  \[7\Omega \]  

C)  \[14\Omega \]              

D)         \[35\Omega \]

Correct Answer: B

Solution :

 The circuit is redrawn as below: It is a typical case of unbalanced bridge. If\[\frac{P}{Q}=\frac{S}{R}=n\]then learn following standard result:                 \[{{R}_{eq}}=\left( \frac{3n+1}{n+3} \right)r\] Here,     \[{{R}_{eq}}=\frac{7}{5}\times 5=7\]