Question

A Vernier caliper has 1 mm marks on the main scale. It has 20 equal divisions on the Vernier scale which match with 16 main scale divisions. For this Vernier caliper, the least count is:

Answer 1

Given,
20 V.S.D = 16 M.S.D
1 M.S.D = 1 mm

1 V.S.D = $\frac{16}{20}$M.S.D

Least count is the difference between one main scale division and vernier scale division.
L.C. = 1 MSD - 1 VSD
L.C. = 1 MSD - $\frac{16}{20}$M.S.D
L.C. = $\frac{1}{5}$M.S.D
L.C. = $\frac{1}{5}\times 1mm$
L.C. = 0.2 mm