question_answer

The equivalent resistance between A and B in the given circuit will be

A)  R                                           

B)  2R

C)  \[\frac{R}{2}\]                 

D)         6/R

Correct Answer: A

Solution :

The given circuit (between A and B) is a balanced Wheat stones bridge. Therefore resistance between C   and D   is ineffective. So, equivalent current is shown in figure. The resistances 2R and 2R are in parallel, so, effective resistance \[{{R}_{eff}}=\frac{{{R}_{1}}{{R}_{2}}}{{{R}_{1}}+{{R}_{2}}}\] \[=\frac{2R\times 2R}{2R\times 2R}=R\]