Question

A cell can be balanced against `110 cm` and `100 cm` of potentiometer wire, respectively with and without being short circuited through a resistance of `10 Omega`. Its internal resistance is
A. `1 Omega`
B. `2 Omega`
C. `3 Omega`
D. `4 Omega`

Answer 1

Correct Answer - A
Given, `l_(1)=110 cm`,
`l_(2)=100 cm`
and `R = 10 Omega`
The internal resistance of the cell
`r=((l_(1)-l_(2))/(l_(2)))R`
`= ((110-100)/(100))xx10=1 Omega`