Question

The vernier scale of a vernier callipers has 20 divisions, and total length of th evernier scale is equal to 18 divisions of the main scale.if one division of the main scale is 0.5 mm, the least count of the instrument is

• A. 0.05 mm
• B. 0.10 mm
• C. 0.20 mm
• D. 0.40 mm

Answer 1

Answer: (A)

0.05 mm

$\text{Given -}\text{vernier scale with}20VSD=18MSD$

$\begin{array}{c}\text{VSD= verenier scale div}\\ \text{MSD= Main Scale div.}\end{array}$

$\text{1 MSD}=0.5mm$

$\begin{array}{cc}\text{Least count}& =1MSD-IVSD=\\ & =1MSD-\frac{18}{20}MSD=\frac{1}{10}MSD\\ & =\frac{1}{10}\times 0.5mm=0.05mm\end{array}$