Question

In the circuit shown, a meter bridge is in its balanced state. The meter bridge wire has a resistance 0.1 ohm/cm. The value of unknown resistance X and the current drawn from the battery of negligible resistance is

• A. $6\Omega ,5A$
• B. $10\Omega ,0.1A$
• C. $4\Omega ,1.0A$
• D. $12\Omega ,0.5A$

Answer 1

Answer: (C)

$4\Omega ,1.0A$

Resistance of the part $AC$

$R_{AC}=0.1\times 40=4\Omega$ and $R_{CB}=0.1\times 60=6\Omega$

In balanced condition $\frac{X}{6}=\frac{4}{6}\Rightarrow X=4\Omega$

Equivalent resistance $R_{eq}=5\Omega$ so current drawn from battery $i=\frac{5}{5}=1A$