Question

A specially designed Vernier calliper has the main scale least count of $1mm$. 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.

$\Rightarrow LC=1MSD-1VSD$

$=(1-\frac{11}{10})MSD$

$=-\frac{1}{10}MSD$

$=-\frac{1}{10}\times 1mm$

$=-0.1mm$

So, magnitude of least count is $0.1mm$.