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

Explanation

Given: For potentiometer , resistance per unit length `=0.1Omega//m`
`e.m.f.(E)=1.5V`, `l=300cm=3m`
Current `(i)=?`
Potential gradient `=(E)/(l)`
`=(1.5)/(3)=0.5V//m`
Potential gradient `=I((R )/(l))`
`=0.5=I(0.1)`
`I=5A`