What should be the size of the slide wire of the potentiometer to make it to achieve high accuracy?
A. As long as possible
B. As short as possible
C. 1 meter
D. Neither too thin nor too thick
Show Answer
Answer: A
Explanation:-
A potentiometer is an instrument designed to measure an unknown voltage by comparing it with a known voltage. This known voltage is supplied by a standard cell or through a reference source. The potentiometer makes use of null or balanced condition for the purpose of measurement.
The potential difference across a length of the potentiometer wire is directly proportional to its Length (or) when a steady current is passed through a uniform wire, potential drop per unit length or potential gradient is constant.
E ∝ L ⇒ E = φL
Where φ is the potential gradient
So, in the case of longer wire, the fall of potential per unit length is small. In other words, the potential gradient is small. Lesser the potential gradient, more accurate is the potentiometer.
Share your understanding of this question with the correct explanation.