19 divisions on the main scale of a vernier callipers coincide with 20 divisions on the vernier scale. If each division on the main scale is of 1 cm, determine the least count of instrument.

 A measuring device that is used for the measurement of linear dimensions. It is also used for the measurement of diameters of round objects with the help of the measuring jaws.

Least Count of Vernier Calliper

The least count of vernier callipers is also known as the vernier constant. It is defined as the difference between one main scale division and one vernier scale division.

It is mathematically given as:

VC = 1 MSD – 1 VSD

When there are n divisions on the vernier scale which coincides with (n-1) division on the main scale, then the least count of vernier calliper is:

LC = (1−(n−1/n) MSD

Therefore, the least count of vernier calliper is 0.1 mm.

Where,

• VC is the vernier constant
• MSD is the main scale division
• VSD is the vernier scale division
• LC is the least count

Solution

Least count = 1− main scale divisions / coinciding divisions onvernier scale ×1 MSD

LC=1/20=0.05 cm

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