Question

Two students X and Y perform an experiment on a potentiometer separately using the circuit diagram shown here. Keeping other things unchanged
(i) X increases the value of resistance R.
(ii) Y decreases the value of resistance S in the setup.

How would these changes affect the position of a null point in each case and why

Answer 1

(i) When the value of resistance R is increased, then the current from the driver cell decreases in the potentiometer, the potential gradient across the wire decreases. Due to this, the balance point is shifted towards the right.

(ii) When the value of resistance S is decreased, the current in the potentiometer increases. Due to this, the balance point is shifted towards left.