Question

N divisions on the main scale of a vernier callipers coincide with N + 1 divisions on the vernier scale. If each division on the main scale is of a units, determine the least count of the instrument.

Answer 1

Correct option: (a)

Explanation:

 Least count of vernier callipers

= value of one division of main scale – value of one

division of vernier scale

Now, N × a = (N + 1) a' 

(a' = value of one division of vernier scale)

∴ Least count = a - a' = a / N + 1