question_answer

In the arrangement of resistances shown below, the effective resistance between points A and B is                                                                        [MP PMT 1997; RPET 2001]

A)                    \[20\,\Omega \]

B)                                      \[30\,\Omega \]

C)                    \[90\,\Omega \]         

D)            \[110\,\Omega \]

Correct Answer: A

Solution :

             By the concept of balanced Wheatstore bridge, the given circuit can be redrawn as follows Þ \[{{R}_{AB}}=\frac{30\times 60}{(30+60)}=20\,\,\Omega \]