Question

A potentionmeter wire has resistance of per unit length of 0.1 Ω/m. A cell of e.m.f. 1.5V balances against 300 cm length of the wire. Find the current in the potentiometer wire.

Answer 1

Given:- σ = 0.1 Ω/m, E = 1.5 V,

              L = 300 cm = 3 m.

To find:- Current through potentiometer (I).

Formulae: i. σ = R/L        ii. I = E/R

Calculation:- From formula (i),

R = σL

   = 0.1 x 3 = 0.3 Ω

From formula (ii),

I = 1.5/0.3 = 5 A

Current through the potentiometer wire is 5 A.