Class 12 NEET Physics Current Electricity Questions Part 1

A potentiometer circuit has been set up for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has an emf of 2.0 V and a negligible internal resistance. The potentiometer wire itself is 4 m long. When the resistance, R, connected acrose the given cell, has values of.
(i) infinity (ii) 9.5Ω
The 'balancing lengths, on the potentiometer wire are found to be 3 m and 2.85 m, respectively.
The value of internal resistance of the cell is: