Question

1 cm on the main scale of vernier calipers is divided into $10$ equal parts. If $10$ divisions of vernier coincide with $8$ small divisions of main scale, then the least count of the caliper is:

• A. $0.01cm$
• B. $0.02cm$
• C. $0.05cm$
• D. $0.005cm$

Answer 1

The correct option is B $0.02cm$

Width of each division $=1cm\times \frac{1}{10}=0.1cm$

Least count of the vernier is equal to the $\frac{10-8}{10}$ times the value of each division.

$⟹$ Least count $=\frac{2}{10}\times 0.1cm=0.02cm$