The least count of an instrument is the smallest measurement that can be taken accurately with it. The least count of the metre scale is 1mm, and that of the ammeter is 2 ampere.
Measurement of Length with a Metre Scale
In daily life, the length is measured with the help of a metre scale. It is graduated in cm and mm, such that the value of one small division is 1 mm. Thus, a metre scale can be used to measure a length accurately up to 1 mm.
Vernier callipers, instruments for making very accurate linear measurements, were introduced in 1631 by Pierre Vernier, a French mathematician. Vernier calipers are widely used in scientific laboratories and manufacturing for quality control measurements.
Vernier Calliper – Parts
1. Main Scale – The main scale is similar to that of a ruler, graduated in mm and cm on one side and inches on the other side.
2. Vernier Scale – The Vernier scale is a sliding scale. It slides parallel to the main scale and enables readings to be made to a fraction of a division on the main scale. The total number of divisions on the Vernier scale is 100.
3. Screw – The Vernier scale can be fixed at any position on the main scale with the help of a screw.
4. Jaws – It has two jaws. The lower jaws are called outside jaws, and they are used to measure the length of a rod, the diameter of a sphere or the external diameter of a cylinder. The upper jaws are called the inside jaws, which are used to measure the internal diameter of a hollow cylinder or pipe.
5. Strip – The thin strip is used to measure the depth of the objects, like beakers.
Least Count of Vernier Calliper
Least count of Vernier calliper = Smallest division on the main scale/Number of divisions on the Vernier scale
Least count of Vernier calliper = 1mm/10 divisions
Least count of Vernier calliper = 0.1 mm
Uses of a Vernier Calliper
Vernier callipers are used to measure
(i) The length of a rod or any object.
(ii) The diameter of a sphere.
(iii) The internal and external diameter of a hollow cylinder.
(iv) The depth of a small beaker.
Units & Dimensions – Vernier Callipers
Units & Dimensions – Important Questions
Frequently Asked Questions on Least Count of Vernier Calliper
What is the least count formula of a Vernier calliper?
The least count of a Vernier calliper is as follows:
LC = Smallest division on the main scale division / Number of divisions on the Vernier scale
What is the value of the least count of a Vernier calliper?
The least count of the Vernier calliper is 0.1 mm.
What is the use of a Vernier calliper?
The Verner calliper is used to find the internal and external dimensions of the object in science labs, the steel industry, medical purposes, the aerospace industry, etc.
What are the two scales of a Vernier calliper?
A Vernier calliper has a calibrated main scale, just like the commonly used ruler and a Vernier scale.