Each division on the main scale is `1 mm`. Which of the following vernier scales give vernier constant equal to `0.01 mm`?

Options

A. ` 9 mm` divided into 10 divisions.
B. `90 mm` divided into 100 divisions.
C. `99 mm` divided into 100 divisions
D. `9 mm` divided into 100 divisions.

Answer

C

Explanation

`100 VCD = 99 MSD`
`:. 1VSD = (99)/(100) MSD`
`LC = 1 MSD - 1 VSD`
`:. LC = 1 MSD - (99)/(100) MSD`
`:. LC = 0.01 MSD`
`:. LC = 0.01 (1 mm) = 0.01 mm`.