Question

The main scale of a vernier callipers has n divisions/cm. n divisions of the vernier scale coincide with (n - 1) divisions of main scale. The least count of the vernier callipers is?​

Answer 1

A vernier works on the principle that

n V = (n - 1) S

n is the number of divisions on the main scale

S is the length of the smallest main scale division

V is the length of a division on the vernier scale

We can rewrite our above equation as

Least count = S - V = S / n

For a simple caliper the main scale would be graduated in mm

There would be 10 vernier divisions for each 9 main scale divisions

The least count would be 0.1 mm