A potentiometer wire of length L and a resistance r are

A potentiometer wire of length L and a resistance r are connected in series with a battery of e.m.f. E0 and a resistance r1. An unknown e.m.f. E is balanced at a length l of the potentiometer wire. The e.m.f. E will be given by :

EMF, E = Kl where K = (V/L) potential gradient

So, E = kl =	E₀rl
	(r + r₁)L

	E₀r	.	l
	(r + r₁)		L

	E₀l
	L

	LE₀r
	(r + r₁)l

	LE₀r
	l r₁