work in progress! Wait for final Blog. Did you know!😯 2 questions have been asked in JEE-Main and 3 in JEE-Advanced on this concept in last 10 years . The measurement of length is necessary in almost all the experiments in Physics. There are experiments where greater accuracy is not required. In such experiments, a meter scale is used to measure distances correctly up to a millimetre. To measure a length correctly up to a fraction of a millimetre, the division must be subdivided. Hence, a meter scale cannot be used in measurements that requires greater accuracy. For accurate measurement up to or of a millimetre, there are various devices that can be used, such as (A) Vernier caliper (B) Screw gauge (I) Vernier caliper:- A Vernier caliper consists of a rectangular steel bar such that inch is marked on one edge and centimetre is on the other edge, as shown in the figure below. It consists of a main scale and over the main scale slides a small scale calle