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Question

In a vernier caliper, 50 vernier scale divisions coincide with 49 main scale divisions. If one main scale division is 1 mm, what is the least count?

This question was previously asked in
RRB ALP 2025 CBT 2 Mechanic Motor Vehicle Question Paper (28-Jul-2026) (Shift 1)
The correct answer is

0.02 mm

To find the least count of a vernier caliper, we need to understand the concept of vernier scale and how it relates to the main scale.

The least count of a vernier caliper can be calculated using the formula:

\(\text{Least Count} = \text{Value of 1 Main Scale Division} - \text{Value of 1 Vernier Scale Division}\)

Let's calculate step by step:

Main Scale Division (MSD): It is given that 1 main scale division equals 1 mm.

Vernier Scale Division (VSD): 50 vernier scale divisions coincide with 49 main scale divisions. Therefore, one vernier scale division is:

\(1 \, \text{VSD} = \frac{49 \, \text{MSD}}{50} = \frac{49 \, \text{mm}}{50}\)

Now, calculate the least count:

\(\text{Least Count} = 1 \, \text{mm} - \frac{49}{50} \, \text{mm}\)

\(\text{Least Count} = \frac{50}{50} \, \text{mm} - \frac{49}{50} \, \text{mm}\)

\(\text{Least Count} = \frac{1}{50} \, \text{mm} = 0.02 \, \text{mm}\)

Thus, the least count of the vernier caliper is 0.02 mm.

This is why the correct answer is the option 0.02 mm.

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Similar Questions

  1. Why are calipers generally used along with a steel rule in workshop measurement?

  2. In a vernier caliper, the small scale that slides along the main scale is called:

  3. Which part of the Vernier caliper slides along the main scale for measurement?

  4. Which application best demonstrates the practical use of outside callipers in automotive work?

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Important Questions from Caliper

  1. How many divisions are graduated on the thimble of micrometer?

  2. The least count of Vernier bevel protractor is ____

  3. In a Vernier calliper, 39 main scale divisions are divided into 40 equal points on the Vernier scale. Then what is its least count (LC) in mm? (Take the value of main scale division = 1mm).

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