AP and TS EAMCET Engineering Model Paper 14

The length of a potentiometer wire is 4m and its resistance is 8Ω. A battery of internal resistance 2Ω and emf 2 volts is connected in series with the wire. A cell in the secondary circuit get balanced at 2.5m length of wire. On drawing the current of 0.2A from this cell, the null point obtained at 2m. The internal resistance of cell in secondary circuit is