In a vernier calliper, 20 VSD coincide with 16 MSD (each division of length 1 mm). The least count of the vernier callipers is:

Question

Accepted Answer

C. 1. Recall the **least count formula** for a vernier caliper.

$$LC = 1\,	ext{MSD} - 1\,	ext{VSD}$$

2. Express 1 VSD in terms of MSD, since the problem states that 20 VSD equal 16 MSD.

$$1\,	ext{VSD} = \frac{16}{20}\,	ext{MSD}$$

3. Substitute this into the least count formula.

$$LC = 1\,	ext{MSD} - \frac{16}{20}\,	ext{MSD} = \frac{4}{20}\,	ext{MSD} = 0.2\,	ext{MSD}$$

4. Convert to centimetres, since $1\,	ext{MSD} = 1\,	ext{mm}$.

$$LC = 0.2\,	ext{mm} = 0.02\,	ext{cm}$$

Hence, the least count is **0.02 cm**, matching option **C**.