In a potentiometer arrangment, a cell of emf 1.25 V gives a balance point at 35.0 cm length of the wire. If the cell is replaced by another cell and the balance point shifts to 63.0 cm`, what is the emf of the second cell ?

Explanation

Here` epsilon_(1) = 1.25 V, l_(1) = 35.0 cm epsilon_(2) = ?, l_(2) = 63.0 cm`
As `(epsilon_(2))/(epsilon_(1)) = (l_(2))/(l_(1))` or
`epsilon_(2) = (epsilon_(1) xx l_(2))/(l_(1)) = (1.25 xx 63)/(35) = 2.25 V`