Physics - Current Electricity Question with Solution | TestHub

Length of the potentiometer wire, $L_0=200$ cm

Potential difference across the wire, $V_0=4$ V

Potential gradient, $k=\frac{V_0}{L_0}=\frac{4}{200}$ V/cm

EMF of the source, $E=2.4$ V

Using the principle of potentiometer, $E=kL$

$2.4=\left(\frac{4}{200}\right)L$

$L=\frac{2.4\times 200}{4}=120$ cm

Answer: $120$ cm.