question_answer

A wire of resistance\[18\,\Omega \]is divided into three equal parts. These parts are connected in side of triangle, the equivalent resistance of any two corners of triangle will be

A)  18\[\Omega \]          

B)  9\[\Omega \]

C)  6\[\Omega \]             

D)  4\[\Omega \]

Correct Answer: D

Solution :

 To find equivalent resistance across BC, AB and AC are in series \[R'=6+6=12\,\Omega \] \[12\,\Omega \]and \[6\,\Omega \]is in parallel Total resistance, \[R=\frac{12\times 6}{12+6}\] \[R=\frac{72}{18}=4\Omega \]