Question

The value of unknown resistance (x) for which the potential difference between B and D will be zero in the arrangement shown, is :

(1) \(3\ \Omega\)

(2) \(9 \ \Omega\)

(3) \(6 \ \Omega\)

(4) \(42 \ \Omega\)  

Answer 1

Correct option is :  (3) \(6 \ \Omega\)

In case of balanced Wheatstone Bridge

\(\frac{\mathrm{V}_{\mathrm{AB}}}{\mathrm{V}_{\mathrm{AD}}}=\frac{\mathrm{V}_{\mathrm{BC}}}{\mathrm{V}_{\mathrm{CD}}} \Rightarrow \frac{12}{6+\mathrm{x}}=\frac{0.5}{0.5}\)

\(\mathrm{x}=6 \ \Omega\)