In a potentiometer experiment, no current passes through the galvanometer when the terminals of the cell are connected across 78 cm of the potentiometer wire. Now the cell is shunted by a resistance of `6 Omega`. A balance point is found across 26 cm of the wire. The internal resistance (in ohms) of the cell is ______

Answer

`12.00`

Explanation

Internal resistance,
`r = (l_(1)/l_(2) -1)R`
`= (78/26 -1) xx 6`
`= ((78 - 26)/26 xx 6)`
`= 52/26 xx 6`
`= 2 xx 6`
`therefore r = 12 Omega`