Correct Answer - Option 1 : 0.1 mm
Concept:
Least count = \(\frac{Smallest\;Division\;on\;main\;scale}{Total\;no.\;of\;divisions\;on\;vernier\;scale}\)
Calculation:
Given:
Smallest division on the main scale = 1 mm
Total number of divisions on vernier scale = 10
Least count = \(\frac{Smallest\;Division\;on\;main\;scale}{Total\;no.\;of\;divisions\;on\;vernier\;scale}\)
Least count = \(\frac{1}{10} = 0.1\; mm\)