In a vernier callipers, 20 VSD coincide with 16 MSD (each division...

Given $20$ VSD $= 16$ MSD.

$1$ VSD $= \dfrac{16}{20}$ MSD $= 0.8$ MSD.

Least count is given by $1$ MSD $- 1$ VSD.

Least count $= 1$ MSD $- 0.8$ MSD $= 0.2$ MSD.

Since $1$ MSD $= 1$ mm, we get Least count $= 0.2$ mm.

Converting to cm, Least count $= 0.02$ cm.

Answer: $0.02$ cm