A potentiometer wire is 100cm long and a constant p.d. is maintained across it. Two cells A and B are connected in series first and then in opposition. The balance points were obtained at 50cm and 30 cm. Find the ratio of the emf of the cells

Options

A. `1 : 2`
B. `3 : 2`
C. `4 : 1`
D. `3 : 5`

Answer

C