Question

Define the least count of vernier callipers. How do you determine it?

Answer 1

The least count of vernier callipers is equal to the difference between the values of one main scale division and one vernier scale division.

Let n divisions on vernier callipers be of length equal to that of (n - 1) divisions on the main scale and the value of 1 main scale division be x. Then,

Value of n divisions on vernier = (n - 1) x

Alternatively, value of 1 division on vernier = `((n - 1)"x")/n`

Least count = `x - ((n - 1)"x")/n = x/n`

L.C. = `"(Value of one main scale division)"/"(Total no. of divisions on vernier callipers)"`

Value of one main scale division = 1 mm

Total no. of divisions on vernier = 10

Therefore, L.C. = `(1 "mm")/10` = 0.1 mm = 0.01 cm