question_answer

The equivalent resistance between A and B is

A)  \[5\,\Omega \]              

B)  \[8\,\Omega \]

C)  \[2.5\,\Omega \]                        

D)  \[6.8\,\Omega \]

Correct Answer: A

Solution :

Equivalent circuit is shown below   \[{{R}_{CD}}\,=\,\,7+2+2=6\,\Omega \] \[{{R}_{CD}}\] is parallel to 60 hence \[\frac{1}{{{\operatorname{R}}_{eq}}}\,=\,\,\frac{1}{6}+\frac{1}{6}\] \[=\,\,{{R}_{eq}}=\,\,3\,\Omega \,\,=\,\,1+3+1=5\,\Omega \]