Question

In a potentiometer arrangement, a cell gives a balancing point at 75 cm length of wire. This cell is now replaced by another cell of unknown emf. If the ratio of the emf's of two cells respectively is 3 : 2, the difference in the balancing length of the potentiometer wire in above two cases will be _____ cm.

Answer 1

$\frac{\epsilon_1}{\epsilon_2}=\frac{l_1}{l_2}$
$\frac{3}{2}=\frac{75\,cm}{l_2}$
$l_2=50\,cm$
$l_1-l_2=75-50=25\,cm$