Question

Consider the vernier calipers as shown, the instrument has no zero error. What is the length of the rod shown ?
Assume that $5^{th}\text{VSD coincides with MSD},1\text{MSD}=1\text{mm}$ and $7\text{MSD}=8\text{VSD}$.

• A. $4.625\text{mm}$
• B. $4.56\text{mm}$
• C. $4.325\text{mm}$
• D. None

Answer 1

The correct option is A $4.625\text{mm}$

Given $7\text{MSD}=8\text{VSD}$.
$\text{VSD}=\frac{7}{8}\text{MSD}$.
$\text{LC}=1\text{MSD}-1\text{VSD}$
$\text{LC}=1\text{MSD}-\frac{7}{8}\text{MSD}$
$\text{LC}=\frac{1}{8}\text{MSD}=\frac{1}{8}\text{mm}$

Length of rod is $=M.S.R.+V.S.R.\times L.C.$

​​​​​​​$M.S.R.=4\text{mm}V.S.R.=5\text{mm}$

$\therefore$ Length of the rod
$l=4\text{mm}+(L.C.)\times 5\text{mm}$
$l=4\text{mm}+\frac{1}{8}\times 5\text{mm}$
$l=\frac{37}{8}\text{mm}$
$l=4.625\text{mm}$