The number of divisions on the vernier scale =50
Main scale division (MSD)=0.5mm
As, 50 divisions on the vernier scale coincide with 49 divisions on the main scale,
VSD=5049MSD
The minimum inaccuracy in the measurement of distance by a vernier scale,
= Least count of the vernier scale
=1MSD–1VSD
=1MSD−5049MSD
=501MSD=501×0.5mm
=0.01mm.