In a potentiometer experiment the balancing length with a cell is 560 cm. When an external resistance of `10Omega` is connected in parallel to the cell, the balancing length changes by 60 cm. Find the internal resistance of the cell.

Explanation

Balancing length `l_(1)=560cm`
Change in balancing length `(l_(1)+l_(2))=60cm`
`560-l_(2)=60`
`thereforel_(2)=500cm`
`r=R((l_(1)-L_(2))/(l_(2)))impliesr=10xx(60)/(500)=(6)/(5)=1.2Omega`