With a certain cell, the balance point is obtained at 65 cm from the zero end of a potentiometer wire. With another cell, whose e.m.f. is less than that of the first by 0.1 V, the balance point is obtained at 60 cm. What is the e.m.f. of the first cell ?

Options

A. `1.0 V`
B. 1.2 V
C. 1.3 V
D. 1.5 V

Answer

C

Explanation

`(E_(1))/(E_(1)-0.1)=(l_(1))/(l_(2))=(65)/(60)=(13)/(12)`
`therefore 13 E_(1)-1.3= 12 E_(1) therefore E_(1)= 1.3 V`