Question

A hypothetical vernier scale of a travelling microscope has 40 divisions which are equal to 38 main scale divisions. If each main scale division is 1.2 mm, the minimum error in the measurement of length is :

• A. 0.6 mm
• B. 1.2 mm
• C. 0.06 mm
• D. 0.1 mm

Answer 1

Answer: (C)

0.06 mm

$\begin{array}{cc}1mSD& =1.2mm\\ 40VSD& =38MSD\\ 1VSD& =\frac{38}{40}mSD\\ & =\frac{38}{40}\times 1.2mm\\ & =\frac{38\times 0.3mm}{100}\\ & =\frac{114mm}{100}\\ & =1.14mm\end{array}$

$\begin{array}{cc}L\cdot C& =1mSD-1VSD\\ & =1.2-1.14\\ & =0.06mm\\ L.C=& \text{min error in}\\ & \text{measurement}\\ & =0.06mm\end{array}$