A potentiometer circuit has been set up for finding the internal resistance of a given cell. The...

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 \( 2.0 \mathrm{~V} \) and a negligible internal resistance. The potentiometer wire itself is \( 4 \mathrm{~m} \) long, When a resistance \( \mathrm{R} \), connected across the given cell, has values of,
(i) infinity
(ii) \( 9.5 \Omega \)
The balancing lengths on the potentiometer wire are found to be \( 3 \mathrm{~m} \) and \( 2.85 \mathrm{~m} \) respectively. The value of internal resistance of the cell is :-
(1) \( 0.25 \Omega \)
(2) \( 0.95 \Omega \)
(3) \( 0.5 \Omega \)
(4) \( 0.75 \Omega \)