Question

a Vernier caliper has 20 divisions on the vernier scale. 1 cm on the main scale is divided into 20 equal parts. Find the least count of of this instrument.

Answer 1

A vernier caliper has 20 divisions on the vernier scale, which coincide with 19 on the main scale. If one main scale division is 2mm, then the least count of the instrument is



VSD - Vernier scale divisions.   MSD - Main scale divisions.  

Given that 20 VSD = 19 MSD
Then 1 VSD = (19)/(20) MSD= 0.95 MSD.

Least count of Vernier calipers, LC  = 1 MSD -1 VSD
            = 1 MSD - 0.95 MSD = 0.05 MSD.
As 1 MSD = 2mm,  
Least count, LC = 0.05 x 2 mm = 0.1 mm.

Answer 2

hey mate ur ans

pitch = unit / division

1/20=0.05

Least count : pitch/VSD


= 0.05/20
=0.0025cm

hope it helps