Question

What is the formula or equation to find the Least Count ?. Please Tell. It's Very Important .✍️✍️✍️

Answer 1

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The smallest value that can be measured by any instrument used in engineering and electrical metres are known as least count.

General formula = $\dfrac{Scale \: reading}{Number \: of \: division \: on \: the \: scale}$

This is for vernier caliper

N division on vernier scale is equal to (N-1) division on the main scale .

N vernier scale division = (N-1) Main scale division

1 Vernier scale division = $\dfrac{N-1}{N} \Big(Main\: Scale \: Division \Big)$

Least count = 1 Main scale division - 1 Vernier scale division

Least count = 1 Main scale division - $\dfrac{N-1}{N}\Big(Main\: Scale\: Division\Big)$

Least count = 1 Main scale division ( 1 - $\Big(\dfrac{(N-1)}{N}\Big)$

Least count = 1 M.S.D $\Big(\dfrac{N\: - N +1}{N}\Big)$

Least count = $\dfrac{1M.S.D}{N}$

Least count = $\dfrac{S}{N}$

S = value of one main scale

N = number of equal division on scale

For example (refer figure)

S = 1 mm

N = 50

Then

Least count = $\dfrac{1}{50}$

Least count = 0.02 mm

Thanks & Regards

S156707