AAI ATC Junior Executive 27 Jul 2022 Shift 2 Paper

A potentiometer wire of length 100 cm has a resistance of 30 ohms. It is connected in series with a resistance of 20 ohms and an accumulator of emf 10 V having negligible internal resistance. A source of 2.4 V is balanced against a length L of the potentiometer wire. What is the value of L?