The Vernier scale is divided into 30 divisions, which coincides with 29 main scale divisions. If eac

Question

The Vernier scale is divided into 30 divisions, which coincides with 29 main scale divisions. If each division is $\frac{1}{2} \mathrm{~mm}$, the least count by the instrument is

Professor PC Thomas Classes · Answer

Least count $= 1 \mathrm{MSD} - 1 \mathrm{VSD} = 1 \mathrm{MSD} - \frac{29}{30} \mathrm{MSD} = \frac{1}{30} 	imes 0.5 \mathrm{~mm} = \frac{1}{60} \mathrm{~mm}$.