In a potentiometer experiment two cells of e.m.f. E and E are used in series and in conjunction and the balancing length is found to be 58 cm of the wire. If the olarity of E is reversed, then the balancing length becomes 29 cm . The ratio `(E_(1))/(E_(2))` of the e.m.f. of the two cells is

Options

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

Answer

B

Explanation

`(E_(1))/(E_(2))=(l_(1)+l_(2))/(l_(1)-l_(2))=(58+29)/(58-29)=(87)/(29)=(3)/(1)`