Question

Figure 3.33 shows a potentiometer with a cell of 2.0 V and internal resistance 0.40Ω maintaining a potential drop across the resistor wire AB. A standard cell which maintains a constant emf of 1.02 V (for very moderate currents upto a few mA) gives a balance point at 67.3 cm length of the Wire. To ensure very low currents drawn from the standard cell, a very high resistance of 600 kΩ is put in series with it, which is shorted close to the balance point. The standard cell is then replaced by a cell of unknown emf 8 and the balance point found similarly, turns out to be at 82.3 cm length of the wire.Is the balance point affected by this high resistance?

Answer 1

The balance point will not be affected by the high resistance of 600kilo ohm or not by the internal resistance of standard cell.

It will be affected by the change in emf of the testing cell.