A Daniel cell is balanced on `125 cm` length of a potentiometer wire. Now the cells is short-circuited by a resistance `2 ohm` and the balance is obtained at `100 cm`. The internal resistance of the Daniel cell is

Options

A. `0.5 Ohm`
B. `1.5 Ohm`
C. `1.25 Ohm`
D. `4//5 Ohm`

Answer

A

Explanation

(a) `r = ((l_(2) - l_(2))/(l_(2))) R = ((25)/(100)) 2 = 0.5 Omega`