Physics - Current Electricity Question with Solution | TestHub

The internal resistance $r$ of a cell determined using a potentiometer is given by the formula:

$r=R\left(\frac{l_1}{l_2}-1\right)$

Given $l_1=240$ cm, $l_2=120$ cm, and $R=2\Omega$.

Substituting the values:

$r=2\left(\frac{240}{120}-1\right)$

$r=2(2-1)$

$r=2\Omega$

Answer: $2\Omega$