This question was previously asked in

UGC NET Paper 2: Electronic Science Nov 2017 Official Paper

Option 2 : Increasing the length of potentiometer wire

CT 3: Building Materials

2962

10 Questions
20 Marks
12 Mins

Standard potentiometer diagram is shown below:

- A to B is the potentiometer wire.
- If the instrument is more sensitive, then the percentage error or relative error will be less.

The output of the voltmeter is \(V = \frac{{dv}}{{dx}} \cdot x\) ---(1)

Where \(\frac{{dv}}{{dx}}\) is the potential gradient equal to potential per unit length.

x is balancing length

v is measuring the potential or output of potentiometer.

From equation – (1)

\(\frac{{dv}}{v} = \frac{{dx}}{x}\) = error (relative error)

So the error is directly proportional to 1/x

If x (Balancing length) is large, the error will be less. This is because the potentiometer becomes more sensitive.

Sensitivity ∝ length of potentiometer wire.

Hence Option (2) is correct