Question

A Vernier caliper has $1mm$ marks on the main scale. It has $20$ equal divisions on the Vernier scale which match with $16$ main scale divisions. For these Vernier calipers, the least count is

• A. $0.02mm$
• B. $0.05mm$
• C. $0.1mm$
• D. $0.2mm$

Answer 1

The correct option is D

$0.2mm$

Step 1. Given data

Marks on the main scale of Vernier calipers$=1mm$

$20$ Vernier scale divisions $=16$ main scale divisions

Step 2. Finding the $1$division of Vernier

According to the question

$20$ Vernier scale divisions $=$$16$ main scale divisions

$1$ Vernier scale divisions $=$$\frac{16}{20}$

$=0.8mm$

Step 3. Finding the least count

By using the formula of least count

Least count $=$$1$ main scale division $-$ $1$ Vernier scale division

$=1mm-0.8mm$

$=0.2mm$

Therefore, the least count is $0.2mm$.

Hence, the correct option is $\left(D\right)$.