In a potentiometer arrangement a cell of emf `1.20 V` given a balance point at `30 cm` length of the wire. The cell a now replaced by another cell of unknown emf. The ratio of emfs of the two cells is `1.5 `, calculate the difference in the balancing length of the potentiometer wire in the two cases

Answer

`10 cm`

Explanation

Given `(epsilon_(1))/(epsilon_(2)) = 1.5 , epsilon_(1) = 1.2 V, l_(1) = 30 cm l_(2) = ?`
`(epsilon_(1))/(epsilon_(2)) + (l_(1))/(l_(2)) or l_(2) = (epsilon_(2))/(epsilon_(2)) l_(1) = (30)/(15) = 20 cm `
Difference in the balancing length of pontionemeter wire `= l_(1) - l_(2) = 30 - 20= 10 cm`