Question

A specially designed Vernier calliper has the main scale least count of $1\, mm$. On the Vernier scale, there are $10$ equal divisions and they match with $11$ main scale divisions. Then, the least count of the Vernier calliper is

• A. 0.1 mm
• B. 0.909 mm
• C. 1.1 mm
• D. 0.09 mm

Answer 1

Answer: (A)

Here, $10$ divisions of vernier scall $= 11$ main scale divisions
So, $1$ vernier scale division $ = \frac{11}{10}$ main
scale divisions
Now, we use formula for least count,
Least count $= 1 $ main scale division $-1$
vernier scale division.
$\Rightarrow LC = 1\,MSD - 1 \,VSD$
$= (1 - \frac{11}{10}) MSD$
$ = - \frac{1}{10} MSD$
$ = - \frac{1}{10} \times 1\,mm$
$ = - 0.1\,mm$
So, magnitude of least count is $0.1\, mm$.