198 An accumulator of emf 2 V and negligible internal resistance is connected across a uniform wire of length 10 m and resistance 30 ohm. The appropriate terminals of a cell of emf 1.5 V and internal resistance 1 ohm is connected to one end of the wire and the other terminal of the cell is connected through a sensitive galvanometer to a slider on the wire. What is the length of the wire that will be required to produce zero deflection of the galvanometer ? How will the balancing length change ? (a) When a coil of resistance 5 ohm is placed in series with the accumulator. (b) The cell of 1.5 V is shunted with 5 ohm resistor ?