Question

A battery having a steady voltage is connected to the ends of 10 m long potentiometer wire.The null point for a Leclaire cell is obtained at 750 cm.If the length of potentiometer wire is increased by 1 m,the new balancing length in metres will be:-

Answer 1

Let the previous balancing length is $l_1=750cm$ and new balancing length is $l_2.$

$\therefore$ for the same potentiometer wire

$\frac{\Delta V}{10}{l}_1=\frac{\Delta V}{11}{l}_2$

$\Rightarrow \frac{750}{10}=\frac{l_2}{11}$

$\Rightarrow l_2=75\times 11=825cm.$

$\therefore$ New balancing length is $825cm.$