NEET Questions

A potentiometer wire of length 100 cm has a resistance of 10 Ω. It is connected in series with a resistance box and a 2V cell of negligible internal resistance. If a cell of emf $E_1$ is balanced against a length of 40 cm and another cell of emf $E_2$ is balanced against a length of 60 cm when the resistance in the box is 10 Ω and 5 Ω respectively, the ratio $\frac{E_1}{E_2}$ is: