A vernier scale is a visual aid that allows the user to measure more precisely than could be done unaided when reading a uniformly divided straight or circular measurement scale. It is a subsidiary scale that indicates where the measurement lies in between two of the graduations on the main scale. Verniers are common on sextants used in navigation, scientific instruments used to conduct experiments, machinists' (or jewelers') measuring tools (all sorts, but especially calipers and micrometers) used to work materials to fine tolerances, on theodolites used in surveying, and in absolute encoders to measure linear or rotational displacements.

Answer:

Small thickness is measured by using a Vernier scale.

The Vernier scale is a device that helps measure small distances or thicknesses with great accuracy. It consists of a main scale and a sliding Vernier scale. The main scale is marked with regular divisions, while the Vernier scale is slightly smaller and has subdivisions that are slightly different from those on the main scale.

The Vernier scale works on the principle of Vernier calipers, which are widely used in scientific and engineering applications. The calipers have two jaws, one fixed and one movable, which can be used to measure the distance between two points. The Vernier scale on the calipers allows for precise measurements by providing additional subdivisions.

The Vernier scale is used to measure small thicknesses by aligning the object being measured between the jaws of the Vernier calipers. The main scale is read at the point where the object ends, while the Vernier scale is read at the point where the line on the Vernier scale aligns with a line on the main scale. The difference between the readings on the main scale and the Vernier scale gives the precise measurement of the thickness.

Using a Vernier scale for measuring small thicknesses offers several advantages. It provides a high level of accuracy, as the Vernier scale allows for measurements down to a fraction of a millimeter. It also allows for easy reading of the measurement, as the alignment of the scales provides a clear indication of the thickness. Additionally, Vernier scales are portable and can be used for measurements in various settings.

In conclusion, a Vernier scale is the preferred instrument for measuring small thicknesses due to its accuracy, ease of use, and portability.

Vernier scale