Question

One main scale division of a vernier callipers is 'a' cm and n^th division of the vernier scale coincide with (n – 1)^th division of the main scale. The least count of the callipers in mm is :

(1) \(\frac{10\,na}{(n-1)}\)

(2) \(\frac{10a}{(n-1)}\)

(3) \((\frac{n-1}{10n})a\)

(4) \(\frac{10a}n\)

Answer 1

Correct option is  (4) \(\frac{10a}n\)