Question

In a vernier callipers, 50 vernier scale divisions are equal to 48 main scale divisions. If one main scale division = 0.05 mm, then the least count of the vernier callipers is ________ mm.

• A. 0.02
• B. 0.005
• C. 0.002
• D. 0.05

Hint:

Least count measures the smallest length an instrument can resolve accurately.

Answer 1

The Correct Option is C

Step 1: Relation between vernier and main scale.
\[ 50 \, \text{VSD} = 48 \, \text{MSD} \Rightarrow 1 \, \text{VSD} = \frac{48}{50} \, \text{MSD} \]
Step 2: Define least count.
\[ \text{Least Count} = 1 \, \text{MSD} - 1 \, \text{VSD} \]
Step 3: Substitute values.
\[ \text{LC} = 1 - \frac{48}{50} = \frac{2}{50} \, \text{MSD} \]
Step 4: Convert into mm.
\[ \text{LC} = \frac{2}{50} \times 0.05 = 0.002 \, \text{mm} \]