In a potentiometer experiment two cells of emf E1 and E2 are used in series and in conjunction and the balancing length is found to be 58 cm of the wire. If the polarity of E2 is reversed, then the balancing length becomes 29 cm. The ratio E1E2 of the emf is
The correct option is
C
3:1
E1+E2=58+29E1−E2=58−29E1E2=58+2958−29=31