Figure shows a 2.0 V potentiometer used for the determination of internal resistance of a 1.5 V cell. The balance point of the cell in open circuit is 76.8 cm. when a resistor of `9.5 Omega` is used in the external circuit of the cell, the balance point shifts to 64.8 cm length of the potentiometer wire. Determine the internal resistance of the cell.

Explanation

`r=((l_(o)-l_(e))/(l_(c)))R=(76.3-64.8)/(64.8)xx9.5`
`r=1.68Omega`