In a potentiometer arrangement, a cell of emf 1.25 V gives a balance point at 30.0 cm length the wire. If the cell is replaced by another and the balance point shifts to 60.0 cm, what the emf of the second cell ?

Explanation

In case of potentiometer ratio of two emfs is,
`(epsilon_(1))/(epsilon_(2)) = (l_(1))/(l_(2))`
`therefore (1.25)/(epsilon_(2)) = (35)/(63)`
`therefore epsilon_(2) = 1.25 xx (63)/(35)`
` therefore epsilon_(2) = 2.25 ` V