Question

Name the instrument that measures small length to highest accuracy.

Answer 1

Screw gauge:

1. A screw gauge is defined as an instrument that is used for measuring the diameter of thin wires, and the thickness of small sheets such as glass or plastics.
2. The formula for the least count of screw gauge is as follows: Least count of screw gauge = (Pitch)/(number of divisions)
3. Least count of micrometer screw gauge = $\raisebox{1ex}{$\left(1mm\right)$}\!\left/ \!\raisebox{-1ex}{$\left(100\right)$}\right.=0.01mm$
4. Some of the major applications of a screw gauge are:

To measure the diameter of a wire and thus its radius.

To measure the thickness of a slab of glass or a sheet of metal.

To measure the diameter or radius of a given lead shot and hence determine its volume.

To measure the exact volume of an irregular lamina of uniform thickness.

Thus, a screw gauge is an instrument that measures small lengths with the highest accuracy.