Question

A 10 metre long wire of uniform cross-section and having a resistance of 20Ω is fitted in a potentiometer. This wire is connected in series with a battery of 5 V along with an external resistance of 480Ω. If an unknown e.m.f. E is balanced at 600 cm of this wire, calculate 

i. the potential gradient of the potentiometer wire and 

ii. the value of the unknown e.m.f. E. 

Answer 1

Given: l = 10m = 1000 cm,

R = 20Ω, E = 5 V, r = 480Ω,

Balancing length, l'= 600 cm

To find: i. Potential gradient (K)

ii. Unknown emf (E)