Question 264 of 404

In the given figure, battery E is balanced on 55 cm length of potentiometer wire but when a resistance of 10 Ω is connected in parallel with the battery then it balances on 50 cm length of the potentiometer wire then internal resistance r of the battery is 

(1) 1 Ω

(2) 3 Ω

(3) 10 Ω

(4) 5 Ω